British Birds - Sample Copy by Nick Askew

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British Birds Volume 103 • Number 4 • April 2010 206 Great Blue Heron on Scilly: new to Britain E. Ashley Fisher 213 Using stable isotopes to investigate the provenance of an Eagle Owl found in Norfolk Andrew Kelly, Kevin Leighton and Jason Newton 223 The breeding population of Northern Wheatears at Clee Hill, Shropshire, 1998–2009 Dave Fulton 229 The decline of the Ring Ouzel in Britain Innes Sim, Chris Rollie, David Arthur, Stuart Benn, Helen Booker, Vic Fairbrother, Mick Green, Ken Hutchinson, Sonja Ludwig, Mike Nicoll, Ian Poxton, Graham Rebecca, Leo Smith, Andrew Stanbury and Pete Wilson

Regular features 240 Letters Eskimo Curlews Andy Stoddart Eagle Owls in Britain Norman Elkins The malar stripe Lars Svensson and Keith E. Vinicombe

243 Notes Red Kites playing catch? David Ferguson Apparent nesting association of Northern Goshawks and Firecrests Geoff Mawson Common Kestrel attempting to predate Hobby chicks at the nest Dean Nicholson Common Ravens and Grey Herons Peter Davis Spotted Flycatcher nest reconstructed for second clutch A. P. Radford Monitoring Hawfinches – another option J. M. S. Lewis

Hazards of man-made material to nesting Hawfinches N. J. Westwood and M. Watson

248 Reviews Collins Bird Guide 2nd edition Helm Dictionary of Scientific Bird Names The Status of Birds in Nottinghamshire Up River: the song of the Esk Wild Skeins and Winter Skies Wildlife Photography Masterclass The Sounds of Raptors and Falcons Peregrine Falcon Populations

253 News and comment Adrian Pitches

257 Recent reports Barry Nightingale and Eric Dempsey

British Birds aims to: O provide a forum for contributions of interest to all birdwatchers in the Western

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Palearctic; O publish material on behaviour, conservation, distribution, ecology, identification, movements, status and taxonomy; O embrace new ideas and research; O maintain its position as the respected journal of record; and O interpret good scientific research on birds for the interested non-scientist.

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Great Blue Heron on Scilly: new to Britain

Ren Hathway

E. Ashley Fisher

Abstract A first-winter Great Blue Heron Ardea herodias was found at Lower Moors, St Mary’s, Isles of Scilly, on 7th December 2007, during a period of sustained westerly winds that extended across the North Atlantic. Its arrival coincided with a deep depression, which moved along the eastern seaboard of the USA bringing snowfall and freezing temperatures, conditions likely to initiate coldweather movements in North America. The age, timing and circumstances of its discovery all point to this being a wild bird that arrived without the benefit of ship assistance, and it has been accepted into Category A of the British List. 206

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Great Blue Heron on Scilly he weather charts on 7th December to be chestnut! I blinked and looked again. 2007 showed that, for the second conYes they were definitely chestnut! My secutive day, tightly packed isobars thoughts turned immediately to the possiwere spanning the entire width of the bility of Great Blue Heron Ardea herodias, a Atlantic, and a quick scan of additional data species I had seen previously in North on my computer monitor revealed that the America and had routinely checked for since continuous flow of gale-force southwesterlies moving to Scilly some eight years earlier. had reached speeds gusting up to 110 kph! Being familiar with Grey Herons A. cinerea at Surely there had to be a storm-driven this site, I was also struck by this bird’s Nearctic vagrant somewhere in Scilly? I kept slightly odd behaviour; it was just hunched telling myself this as I spent the morning at up and standing motionless behind the vegework, daydreaming about all manner of postation, in an area I knew to be surrounded by sibilities. Since it was December, options of deep water and rarely frequented by Grey what could realistically be expected to turn Herons, even at low water. The hairs on my up in these conditions were fairly limited, nape stood up and I got a massive jolt of although this belief is actually a direct conadrenalin! My excitement was tempered by tradiction of one of my ingrained Scilly an equal measure of incredulity. I rang Bob edicts – expect the unexpected. I thought that Flood, giving him an excited account of the Laughing Gull Larus atricilla would do very features I had seen – he knew exactly what I nicely indeed, especially as I had missed out was thinking and set off in my direction from on finding one during the 2005 influx. With Porth Hellick. this in mind, I set out for Porthloo beach to The bird remained motionless for what check the gulls which feed over the windseemed like an eternity before it suddenly driven, hide-tide surf, but when I got there moved across a small opening and vanished the wind was just too strong and the tide too into an adjacent patch of Phragmites. high. Within minutes, my bins were covered Although views were brief and the bird still in sea spray and my eyes full of sand! I largely silhouetted, I instinctively checked for needed calmer conditions and decided that the rufous thigh feathering; but the light was the shelter provided by Lower Moors might just not good enough and I was able to see be a more productive option – at least there only that the thighs were dark – not white as was a chance of a lingering Wilson’s Snipe on some Grey Herons – and that the feathGallinago delicata still being there. ering appeared noticeably longer. The bird’s It was about 2.00 pm by the time I reached the Hilda Quick hide but the light there was awful, bright sunlight was streaming in through the window and reflecting off the water. Scanning through my salt-coated bins, I noticed a ‘grey heron’ almost entirely obscured behind a patch of Juncus farther back. Through the haze I could just about make out its left shoulder and noted that the carpal/mar- 110. First-winter Great Blue Heron Ardea herodias, Lower Moors, ginal coverts appeared St Mary’s, Isles of Scilly, December 2007. British Birds 103 • April 2010 • 206–212

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Will Wagstaff

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Fisher size and structure were, however, markedly different from what I would have expected of a Grey Heron. Even without direct comparison, it was noticeably larger than a Grey Heron, with a proportionately longer neck and longer legs. Incredulity aside, by now I was becoming convinced that it must be a Great Blue Heron; it just had to be! I gave Bob a quick update and then sprinted round to the ISBG hide. The patch of Phragmites into which it had disappeared was only about 6 m from the ISBG hide, so I opened the slat just a crack for fear of flushing it. From this side of the pool the light conditions were perfect. Slowly, the heron’s head and neck appeared. Although it was still partly hidden in the Phragmites, this was not like any Grey Heron I had seen before! Through the partially open slat, I could make out only the head and neck. The bill was large and two-toned, blackish on the upper mandible and yellow on the lower becoming slightly more orange distally. Side-on, the culmen appeared almost straight. The lower mandible ran parallel to the culmen for about two-thirds of its length before noticeably curving upwards towards the tip, forming a prominent gonydeal angle. The neck sides were subtly mottled dull grey and there was a faint rufous tint increasing in strength towards the fore-neck. It also showed rusty and grey-striped ‘epaulettes’ at the bend of the wing. Abruptly, the heron walked into full view and point-blank range, just 6 m away. I nearly had a coronary! It was absolutely stunning! I checked the thighs and they were a beautiful chestnut/ rufous colour, as were the marginal coverts and the tips to the lesser and median coverts. It also had some distinctly blue-tinged feathers on the otherwise dull grey mantle. It was an absolute classic juvenile Great Blue Heron! I triplechecked all the relevant identification features I could recall and all were consistent with my initial identification. At that point, I was acutely aware that, if it flew off, not only would I be the only observer to have seen it, but the only record, apart from my field notes, would be a few (initially rather poor) ‘digibinned’ images. Moments later and to my great relief, Bob entered the hide and was the recipient of some rather colourful language, interspersed with ‘it is, it 208

is, it is!’ Shortly afterwards, Will Wagstaff arrived and the news went out nationally, while I rang all the local birders, who, one by one, arrived in the hide with shocked looks on their faces. For the first half-hour or so, it was almost comical as we sat there viewing the heron through the narrow gap in the slats. As we gained confidence that it would not flush, we carefully opened them more fully. The bird seemed a little nervous, however, and moved out towards the island on the scrape. Now we all enjoyed excellent views and many superb photographs were taken by Will and Martin Goody. After about 30 minutes, unprompted, it flew off towards Shooter’s Pool. Apart from its obvious large size, the most notable feature was its long legs and feet, clearly projecting farther beyond the tail than in Grey Heron and strongly reminiscent of Purple Heron A. purpurea. After a while it flew again, this time in the company of two Grey Herons. The difference in size and structure was marked; the Great Blue was clearly larger, broader-winged, had distinctly longer legs and showed a more prominent neck bulge. It then returned to Lower Moors, where it remained until dusk. Overnight, weather conditions worsened and gale-force winds were accompanied by torrential rain. Despite this being weather that no bird would voluntarily depart in, there was no sign of the heron the following morning. Around 70 or more twitchers arrived in Scilly the next day, but an extensive search of likely sites, including Lower Moors, Porth Hellick Pool and the entire coastline of St Mary’s, failed to relocate the bird. The search continued over the following days and extended to suitable sites on Tresco, but the Great Blue Heron was not seen again.

Detailed description General appearance Although the plumage was superficially similar to Grey Heron, the most striking differences were the chestnut/rufous thighs, fringes to the carpal and marginal coverts, and tips to the lesser and median coverts. Structurally, it differed from Grey Heron, even without the benefit of direct comparison, appearing larger and (proportionately) longer-necked with a larger head and heavier British Birds 103 • April 2010 • 206–212

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Great Blue Heron on Scilly bill. The legs were also markedly longer and projected well beyond the tail in flight, strongly reminiscent of Purple Heron. Indeed, the bird spent much of the first half hour of observation wading in the deepest area of the pool (an area not frequented by Grey Herons), occasionally with its ‘rear end’ (primaries, tertials and tail) partially submerged. Direct comparison in flight with Grey Heron confirmed many of the above size and structural differences, with the bird appearing clearly larger and broader-winged than that species, and with a more prominent ‘neck bulge’.

Head

Neck The neck appeared proportionately long and noticeably longer than that of Grey Heron. Indeed, the ‘neck bulge’ was comparatively more prominent in flight. On a cursory glance it appeared brownish-grey on the sides, but on closer inspection was neatly mottled dull grey with a subtle rusty tint, increasing in strength towards the fore-neck, which was otherwise whitish, narrowly streaked grey. ‘Epaulettes’ streaked rufous, grey and off-white.

Upperparts Mantle, scapulars, back, rump and uppertailcoverts dull grey. Several distinctly bluishtinged feathers noted in the mantle, these presumably being newly replaced first-winter feathers. Tail short, dull grey.

Underparts Breast and belly off-white, streaked grey.

Will Wagstaff

Forehead and crown, including sides of crown, largely blackish-grey, forming a cap; at times this appeared plain blackish, although the forehead was perhaps a shade paler and not as solidly dark, with an illdefined, pale greyish-white wedge in front of the eye. Some feathers of the forehead and crown were often held erect, forming a ragged crest. The head plumes were blackishgrey and relatively short, tapering to a moderate point along the nape. The ear-coverts were contrastingly greyish but not solidly so,

i.e. ‘hollow centred’, bordered below by a distinct dark gape line. The lores showed a narrow, diamond-shaped area of pale, yellowish-green skin, framed above and below by dark grey feathering. The chin, throat and the rear part of the ear-coverts were white.

111. First-winter Great Blue Heron Ardea herodias, Lower Moors, St Mary’s, Isles of Scilly, December 2007. British Birds 103 • April 2010 • 206–212

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Fisher Flanks dark grey, appearing noticeably darker than on Grey Heron. Thigh feathering at the top of the tibia uniformly rufous, but appeared to be narrowly streaked whitish when viewed at close range through a telescope, and this area of feathering seemed to be more extensive along the tibia than on Grey Heron. Vent and undertail-coverts dull white.

Upperwing Marginal and carpal coverts conspicuously chestnut, the latter with some white. Lesser coverts dull grey, the lower row clearly tipped rufous. Median coverts similar but with broader, rufous, drop-shaped tips and whitish terminal spots. Greater coverts broadly similar, though at times appeared paler, and had very narrow greyish-white fringes, broadening slightly at the tips, with a diffuse rufous tinge subterminally. Tertials dull grey, narrowly fringed paler greyishwhite, and noticeably worn at the tips. Primaries and secondaries blackish-grey.

Underwing Seen very well on numerous occasions as the wings were often raised and flapped when it was adjusting its balance to counteract the frequent gusts of wind. Lesser and median underwing-coverts blackish-grey, although some rufous was noted on the lesser primary coverts in photographs, but not noted in the field, contrasting noticeably with paler greater underwing-coverts.

Bare parts The bill looked larger, heavier and less evenly tapered than in Grey Heron. Side-on, the culmen appeared almost straight, with the lower mandible running parallel to this for about two-thirds of its length before noticeably curving upwards towards the tip, forming a prominent gonydeal angle. The upper mandible was almost entirely black, except for a dull, dirty orange cutting edge. The lower mandible was pale greenish-yellow becoming distinctly more orange distally. Iris yellow. Legs two-toned; dull greenish-yellow with a diffuse, dirty blackish-brown wash on the outside of the knee and tarsus. They looked noticeably longer than the legs of Grey Heron, even without direct comparison and, consequently, the bird tended to fre210

quent the deeper areas of the scrape not used by Grey Herons – indeed, water levels were particularly high at Lower Moors on 7th December.

Weather At the time of the heron’s discovery, strong winds were coming straight across the North Atlantic, caused by a deep depression that moved northeast along the eastern seaboard of the USA on 3rd and 4th December, bringing with it a very cold air mass to its rear. This strong northwesterly airflow brought widespread precipitation, mostly as snow, and subzero temperatures to the northeastern states of the USA and eastern Canada – a classic weather pattern likely to initiate cold-weather movements in North America. A likely scenario would have seen the Great Blue Heron moving ahead of this cold air mass on 4th December, which would have brought it into the strong westerly airflow over the western Atlantic. Here it would have involuntarily overtaken the cold fronts and then moved into a much warmer airstream with very strong (and still strengthening) WSW winds that would then have led to a rapid flight across the North Atlantic, arriving on Scilly on 6th. In this warm sector, surface wind speeds to the southwest of Britain & Ireland were being reported as 60–65 kph, with sustained winds reaching 100 kph at an altitude of 1,000 m. In these winds, it is likely that the Great Blue Heron made an unassisted crossing of the North Atlantic in just under the two days, covering a distance of approximately 5,000 km in this period, which would be entirely possible if it was travelling at an average sustained speed of c. 100 kph.

Great Blue Heron in the Western Palearctic Although this was the first Great Blue Heron to reach Britain, its arrival here had been widely predicted. In fact, there have been two previous records of the species reaching British waters, but both individuals were fed aboard a ship, which excludes them from the British List. One of these arrived on board a ship that docked in Avonmouth in November 1968. After being taken into care, it was treated at the Rode Tropical Bird Park British Birds 103 • April 2010 • 206–212

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Great Blue Heron on Scilly do reach this side of the Atlantic. Although ship-assisted vagrancy is a complication when considering records of this species, there have now been records from France, the Canary Islands and several from the Azores, which suggest that unassisted vagrants do reach the Western Palearctic. In the case of the St Mary’s bird, there was no evidence to suggest that it could have been held captive on a ship or fed during a voyage; if fact, the prevailing weather conditions supported a rapid transatlantic crossing.

Azores A minimum of 24 Great Blue Herons have reached the Azores since the first in 1984. Of these, the records from late March (1) and April (9), and October–November (11) coincide with peak passage periods in spring and autumn in North America. Within these periods, there were two notable influxes, accounting for no fewer than 15 individuals, with eight arriving in April 1984 (Le Grand 1986), and seven in October–November 2006 (http://azores.seawatching.net/index.php? page=greatblue). There have also been single records in June (1984), July (2008) and September (2005)(http://azores.seawatching.net/ index.php?page=rarebirddata&id=309# NotFirst).

Will Wagstaff

in Frome, Somerset, where it was placed in an open aviary from which it departed when it had recovered, never to be seen again (King 1978). The second bird died at sea within 250 km of the Isles of Scilly in May 1982, well within the BOU recording limit, but unfortunately after eating fish provided by the crew (Casement 1995). It seems perhaps surprising that such a large and conspicuous species had not been discovered in Britain earlier, particularly when viewed in the context of 40 American Bitterns Botaurus lentiginosus (albeit only eight since 1950), six Green-backed Herons Butorides virescens and one Snowy Egret Egretta thula which have made the crossing. Perhaps Great Blue Heron is less able to survive the transatlantic crossing than its smaller congeners? Although there is no means of establishing whether this is the case, exhausted Great Blue Herons appear to make temporary use of ships in mid Atlantic when the opportunity arises (e.g. King & Curber 1972, Casement 1995, Herroelen 1995). One of the birds that made landfall in the Azores in April 1984, and subsequently died, had anti-rust paint on its back, while three others that succumbed had grease on their feet (Le Grand 1986). So there is little doubt that ship-assisted Great Blue Herons

112. First-winter Great Blue Heron Ardea herodias, Lower Moors, St Mary’s, Isles of Scilly, December 2007. British Birds 103 • April 2010 • 206–212

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Fisher Canary Islands One was found on Tenerife on 5th December 1998 (Clarke 1999).

France The first for Europe was an adult on Île d’Ouessant, Finistère, in April 1996 (Dubois et al. 1997).

Range Great Blue Heron is a widespread breeding bird in North America, with its northern limit extending into southeast Alaska. Across Canada it breeds from northern British Columbia, east through the central Canadian provinces to southern Ontario, southern Quebec and the Canadian maritime provinces including Nova Scotia. It breeds widely throughout the USA south to Florida, Texas and southern California, and south through Mexico and Central America to Belize and Guatemala. Resident populations also occur in Cuba and Jamaica, and it has recently bred in Bermuda where migrants occur regularly. Northern birds are migratory, with dispersing birds reaching Newfoundland, Canada, and Greenland. It winters to the south of the breeding range, mostly to the south of Canada and mid-west United States, with some birds reaching the islands of the Caribbean, and coastal northern South America to Colombia.

The nominate form, herodias, breeds throughout much of North America with the exception of western North America, where the race fannini occurs, which is darker and shorter-billed than herodias. In southern Florida the entirely white form occidentalis is largely resident. Although this was formerly thought to be a separate species, hybrids with nominate herodias are known from the Florida Keys, where they are known as ‘Wurdemann’s Heron’. An isolated race, cognata, breeds on the Galapagos Islands. Acknowledgments Norman Elkins kindly provided a summar y of the weather leading up to 7th December 2007. References British Ornithologists’ Union (BOU). 2009. Records Committee: 37th Report. Ibis 151: 224–230. Casement, M. 1995. Great Blue Herons in the North Atlantic. Birding World 8: 424–425. Clarke,T. 1999.The Great Blue Heron on Tenerife. Birding World 12: 158–161. Dubois, P. J., & le CHN. 1997. Les oiseaux rares en France en 1996. Rapport du Comité d’Homologation National. Ornithos 4 (4): 141–164. Gantlett, S. 1998. Identification of Great Blue Heron. Birding World 11: 12–20. Herroelen, P. 1995. A Great Blue Heron in the North Atlantic. Birding World 8: 356. King, B. 1978. Great Blue and aberrant Grey Herons. Brit. Birds 71: 420. — & Curber, R. M. 1972. Great Blue Herons coming on board ships in mid Atlantic. Brit. Birds 65: 442. Le Grand. G. 1986. Great Blue Herons on Azores in April and June 1984. Dutch Birding 8: 55–57.

E. Ashley Fisher, Trehill, Silvester’s Lane, St Mary’s, Isles of Scilly TR21 0NA

Editorial comment Adam Rowlands, Chairman of BBRC, commented: ‘The identification of Great Blue Heron in a vagrant context has been well covered (e.g. Gantlett 1998). The occurrence of this species in the UK has long been anticipated, but it is still a considerable credit to the bird’s finder that he had an active search-image for this species and was able to confirm the identification and spread the news very quickly. Despite the heron being a one-day occurrence, the finder also submitted excellent documentation in support of the claim, which made the assessment of the identification straightforward for BBRC.’ Bob McGowan, Chairman of BOURC, commented: ‘This was one of the more straightforward assessments for a potential addition to Category A in the last few years, not least due to the very high standard of the submission documentation, including good-quality images. Identification of a juvenile Great Blue Heron was easily established. There was no evidence to suggest that the bird had benefited from assisted passage or any evidence of possible escape risk in Europe. Equally, the age of the bird, the date, weather and locality were convincing for genuine vagrancy. Without biometrics, a definitive statement on racial identity was impossible, though the Committee recognised that nominate herodias is the most likely on the basis of distribution and migratory behaviour. Following a speedy electronic circulation of the record, Great Blue Heron was unanimously accepted to Category A (BOU 2009).’ 212

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Using stable isotopes to investigate the provenance of an Eagle Owl found in Norfolk Andrew Kelly, Kevin Leighton and Jason Newton Abstract The stable isotopes of hydrogen, oxygen, carbon and nitrogen were analysed in two generations of feather growth in a second- or third-calendar-year female Eagle Owl Bubo bubo found in Norfolk in November 2006. We found that the juvenile primaries and secondaries had a consistently low δ2H signature, while second-generation remiges, and body feathers, revealed higher values. The pattern in δ 2 H between the two generations of feathers from the Norfolk bird corresponds with the known moult patterns of Eagle Owls and suggests that the two generations of feathers were grown in different geographical regions. Although there are a number of alternative explanations for the findings, it seems most likely that the owl was reared somewhere with low local δ2H precipitation values. An origin in Scandinavia, north-continental Europe or mid-continental Russia is consistent with our findings, but we cannot rule out the possibility that the bird was reared in northern Britain, either in the wild or in captivity. he recent establishment of breeding pairs of Eagle Owls Bubo bubo in Yorkshire and Lancashire has generated a great deal of publicity in recent years and has sparked a debate about whether the species should be considered a native part of the British avifauna (see Melling et al. 2008 for a review). The presence of jesses (leather straps used in falconry) indicated that one member of a pair nesting in Lancashire in 2006 was indeed an escaped captive bird and many conservation organisations, including the RSPB, maintain that Eagle Owls should probably not be considered a native element of the British avifauna. However, there is speculation that there could be as many as 40 pairs nesting in the UK (Dennis 2005) and an alternative view among the birding community is that the Eagle Owl should be considered a native British species. This is not a pedantic point. Its status has profound impli-

cations for the Eagle Owl’s conservation and welfare. Calls have been made for breeding Eagle Owls to be culled, to protect native species that may be predated by the owls. However, if included as part of the native British avifauna, the Eagle Owl would no doubt be subject to a conservation programme to encourage its re-establishment. Historically, the fossil and archaeological record suggests that the Eagle Owl (or a closely related ancestor) had been present in Britain for up to 700,000 years until the end of the last ice age (Stewart 2007). However, in 1996 the Eagle Owl was removed from the British List by BOURC (BOU 1997), based on a lack of evidence that Eagle Owls have lived in Britain in a wild state for over 200 years. Even though some pairs have bred in Britain, there is no evidence to suggest that these have involved wild birds, and some are known to have been escapes (the species has 213

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Kelly et al. been held in captivity in Britain since the seventeenth century). The Eagle Owl is currently regarded as a non-native species in Britain (Dudley et al. 2006). An alternative view is that Eagle Owls are capable of flying across the North Sea and may have colonised Britain from northern Europe or Scandinavia (e.g. Dennis 2005). Although the species is considered to be relatively sedentary, recent evidence has suggested that young birds may disperse widely. The breeding pair in Yorkshire produced 23 young between 1997 and 2005 (Holling et al. 2007) before the female was shot. One young bird was recovered dead (having hit power lines) over 200 km away in Shropshire the year after fledging and another was found dead near Peebles, Borders, more than 150 km from the nesting site. Ringing records from Norway show movements of between eight and 220 km (mean 95 km, n = 12), with a tendency for birds to move towards the coast (Cramp 1985). In Switzerland, satellite telemetry and radio-tracking studies showed that young Eagle Owls left the natal site between August and November, covering between four and 35 km per night, and travelling up to 320 km in total before settling up to 100 km from the natal territory (Aebischer et al. 2005). More recently, another young Swiss Eagle Owl moved a total of 480 km after leaving its parents, finally settling 120 km from its natal territory (Aebischer et al. 2010). One ringed in Finland was recovered more than 400 km from its natal area (A. Aebischer pers. comm.) and another from Schleswig-Holstein, in Germany, where the species is expanding its range, was recovered on the French Atlantic coast, having travelled at least 1,179 km (Hamann 2002). Clearly, individual birds are capable of large movements over land at least. For the Eagle Owl to be admitted to the British List on the basis of natural occurrence, there would need to be strong supporting evidence (Melling et al. 2008). To date there have been no ring-recoveries of continental Eagle Owls in Britain. This is perhaps not surprising given the small number of individuals marked (see Melling et al. 2008), and the lack of recoveries is not evidence that the species is incapable of crossing the North Sea. Stable-isotope ratios 214

(e.g. 2H/1H, expressed as δ2H) have been used extensively in the past decade as a forensic method of determining the origins and movements of migratory animals (e.g. Hobson et al. 2004, Rubenstein et al. 2004, Bearhop et al. 2005, Bowen et al. 2005, Neto et al. 2006, Fox & Bearhop 2008). For example, Bearhop et al. (2005) used hydrogen-isotope ratios in the claws of Blackcaps Sylvia atricapilla to infer dichotomous wintering areas of birds returning to their breeding grounds in south-central Europe. Neto et al. (2006) used hydrogen, carbon and nitrogen isotope ratios in conjunction with the known moult pattern of Savi’s Warblers Locustella luscinioides to show that the isotope ratios of feathers grown in Europe differed significantly from those grown in the birds’ wintering grounds in subSaharan Africa. Newton et al. (2006) found a wide range of hydrogen isotope ratios in the feathers of ‘Northern Bullfinches’ Pyrrhula p. pyrrhula sampled from Scotland, Denmark, Sweden and the Amur region of Siberia, with those from Sweden and Amur being significantly more depleted in deuterium (2H). Fox et al. (2007) used both hydrogen and oxygen isotope ratios in an analysis of the feathers of a Baikal Teal Anas formosa shot in Denmark in 2005, and distinguished juvenile feathers with a strongly continental signature from post-juvenile ones with a signature more typical of a moist, coastal European environment. Stable isotopes of hydrogen have also been used to infer the origins of Goldfinches Carduelis carduelis trapped in northeastern Europe and imported into the UK illegally (Kelly et al. 2008). Here, we used stable-isotope analysis to investigate the provenance of a second- or third-calendar-year female Eagle Owl found in Norfolk in November 2006. The bird had no rings and there was no evidence (such as feather wear on the primaries) to suggest that it had been held in captivity. We compared the isotope ratios in the primaries, secondaries and body feathers of the Norfolk bird with those collected from the carcases of five wild-bred Eagle Owls from Norway, two from the Netherlands, and a known captive bird found dead near Bristol. We tested the hypothesis that the Norfolk bird had crossed the North Sea and predicted British Birds 103 • April 2010 • 213–222

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Eagle Owl provenance using stable isotopes from two Tawny Owls Strix aluco from Norfolk (a sedentary and resident species). In addition, we also measured the carbon and nitrogen stable-isotope ratios of the feathers. This was partly in an attempt to detect any dietary differences among the birds in this investigation; carbon isotope ratios are a broad indicator of carbon source for the diet, for example C3 or C4 primary production, whereas nitrogen isotope ratios generally indicate the trophic level at which these birds are feeding. Secondly, despite the caveats just mentioned, in conjunction with the hydrogen isotope measurements, δ 13C may confirm or support any geographical inferences made from the δ2H results (Neto et al. 2006).

Methods Circumstances, identification and assessment of moult status On 20th November 2006, a large owl was found in an aircraft hangar at the former RAF base at Watton, Norfolk, by a member of the public. The bird was subsequently collected by an RSPCA Animal Collection Officer and taken to RSPCA East Winch

Markus Varesvuo

that the stable-isotope signatures of juvenile feathers would be similar to those found in continental Eagle Owls. We compared the hydrogen isotope ratios of the feathers with those shown in maps (‘isoscapes’) depicting the predicted isotope ratios of precipitation across north and central Europe (www.waterisotopes.org). We are well aware of the limitations of this approach and recognise that assigning geographical origin based on isotope maps can be misleading unless the tissue samples are compared with those of known origin (Wunder et al. 2005). However, our intention is to contribute to the body of evidence concerning the status of the Eagle Owl in Britain, rather than to determine conclusively the origin of the Norfolk bird. On the basis of the known moult patterns of Eagle Owls (Niiranen & Haapala 1987), we looked for dichotomous origins of feathers and predicted that, if the bird had originated in continental Europe or Scandinavia, we should be able to differentiate between juvenile feathers grown at the natal site and postjuvenile feathers grown in Britain. As a control for hydrogen isotope ratios, we also compared the feather samples with those

113. Eagle Owl Bubo bubo, Helsinki, Finland, December 2006. British Birds 103 • April 2010 • 213–222

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Kelly et al. Wildlife Centre, where it was identified by KL (a BTO A-permit ringer) as an Eagle Owl, based on its appearance and measurements. The bird was examined by a veterinary surgeon and was found to be emaciated and to have an injured eye. Owing to its poor prognosis, it was subsequently euthanised to prevent further suffering. A post-mortem examination revealed that it was a female. Its wing length (max. chord) was 483 mm, placing it in the mid/upper range for the nominate race bubo (Snow & Perrins 1998). The moult of Eagle Owls is poorly known and the following account is based on Niiranen & Haapala (1987). Juveniles have a dark band near the tip of the primaries, secondaries and tail feathers, but in the case of post-juvenile feathers this dark bar tends to be farther from the feather tip. There is large variation in the moult pattern of Eagle Owls and individuals typically show distinctly asymmetric patterns of wing moult. Primary moult usually starts from two focus points. The first series starts at P6/P7 (primaries numbered descendantly, in other words P10 is the outermost), proceeding inwards and towards the tip, but before the outermost primaries are dropped a second series starts from P1. In most cases P3 or P10 is the last to be moulted. Secondary moult proceeds from three focus points, starting with S16 (the innermost) and moving towards the wingtip. The second series starts at S5 and the third series at S2; in most cases, the outermost (S1) is the last to be moulted. Niiranen & Haapala (1987) stated that Eagle Owls undergo a partial moult between May and October during which the body feathers and some wing-coverts are replaced. The innermost secondaries and the tertials are also replaced. Typically, all the tail feathers are replaced between the second and third calendar-year. However, primary moult does not start until the third calendar-year, with P6 or P7 being replaced first. The moult details of the Norfolk Eagle Owl were as follows (with feathers classified as adult- or juvenile-type according to pattern and wear): Left wing P1–P6 juvenile (-type), P7 adult (type), P8–P10 juvenile, S1–S6 juvenile, S7–S14 adult, tertials adult (S15–S16 missing) 216

Right wing P1–P7 juvenile, P8 adult, P9–P10 juvenile, S1–S3, S6–S7 juvenile, S4–S5, S8–S15 adult, tertials adult (S16 missing) Tail T1–T4 adult, T5–T6 juvenile (where T1 is the innermost) Based on this information, the Norfolk specimen was considered to be a second-/ third-calendar-year bird.

Sampling P1–P10 and S1–S14 were taken from the left wing of the Norfolk specimen and placed in polythene sample bags. Tail feathers T1–T6 (left side) and a small number of body feathers removed from the breast were treated similarly. Primary, secondary and breast feathers were taken from two adult Eagle Owls from the Netherlands and secondaries were taken from five adult Eagle Owls from Norway. All the birds from the Netherlands and Norway were recently archived specimens. Primary, secondary and breast feathers were also taken from two adult Tawny Owls from Norfolk and a dead adult Eagle Owl found in Bristol, which was known to be an escaped captive-bred bird. In addition, the outermost primary, outermost secondary and breast feathers of two adult Eagle Owls captive-bred in the UK were collected. Table 1 lists the feathers sampled from each bird. Primaries, secondaries and body feathers were requested for the Norwegian and Dutch birds, but only secondaries were available from the Norwegian birds.

SI preparation and analysis The methodology is given in Appendix 1. For a full explanation of the stable-isotope technique and its application to ornithology, see Fox & Bearhop (2008).

Results Hydrogen and oxygen isotope measurements For the Norfolk Eagle Owl, the δ18O values overlapped considerably: for juvenile-type feathers 11.9–19.0‰ (mean 16.6, SE ±0.4‰) and for adult-type feathers 12.8–17.4‰ (15.8, ±0.4‰). Hydrogen isotope ratios of feathers from the Norfolk bird showed a clear pattern (see fig. 1). P7, S7–S14, T1–T4 and breast feathers of the Norfolk Eagle Owl were enriched in British Birds 103 • April 2010 • 213–222

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Eagle Owl provenance using stable isotopes 2H, relative to P1–P6, P8–P10 and S1–S6. The δ2H values for juvenile-type feathers ranged from -86.9‰ to -96.5‰ (mean -90.1, SE ±0.5‰) and for adult-type feathers from -24.0‰ to -61.7‰ (-43.8, ±2.7‰). There was no overlap in the δ2H values for juvenileand adult-type feathers. The δ2H of the Norwegian Eagle Owls also showed a wide variation, from -1.7‰ to -80.3‰ (-50.6, ±15.3‰) (see fig. 2). This may be related to the variation in latitude from which the birds were obtained (58–69°N) or, alternatively, to the proximity of the ocean of sites from which the samples were obtained. The Norwegian owls consisted of three females and two males. Interestingly, the three birds closest in δ2H values

to the Norfolk owl were all females, while the two most enriched birds were males. However, the reasons for this are not clear and the small sample size makes interpretation difficult. Dual hydrogen and carbon isotope ratios of feathers from the birds from the Netherlands and Norway, two wild-bred Tawny Owls and known captive-bred Eagle Owls are shown in fig. 2.

Carbon and nitrogen isotope measurements The δ13C values of feathers from the Norfolk Eagle Owl formed a narrow range, from -23.9‰ to -22.3‰. Most of the other UK samples, including those from the Tawny

Table 1. Feathers sampled from the Norfolk Eagle Owl Bubo bubo, from wild-bred Eagle Owls from the Netherlands and Norway, and from captive-bred Eagle Owls from Bristol and Wales. Samples from wild Tawny Owls Strix aluco bred in Norfolk are included for comparison. Species Eagle Owl

Status Unknown

Source Norfolk

Feather type Primary Secondary Body Tail

Description P1–P10 S1–S14 Breast T1–T6

Eagle Owl

Wild

Netherlands

Primary Secondary Body

P10 S5 Breast

Eagle Owl

Wild

Netherlands

Primary Secondary Body

P10 S5 Breast

Eagle Owl

Wild

Norway

Secondary

Eagle Owl

Wild

Norway

Secondary

Eagle Owl

Wild

Norway

Secondary

Eagle Owl

Wild

Norway

Secondary

Eagle Owl

Wild

Norway

Secondary

Eagle Owl

Captive

Bristol

Primary Secondary Body

P4 S1 Breast

Eagle Owl

Captive

Wales

Primary Secondary Body

P10 S1 Breast

Eagle Owl

Captive

Wales

Primary Secondary Body

P10 S1 Breast

Tawny Owl

Wild

Norfolk

Primary Secondary Body

P10 S1 Breast

Tawny Owl

Wild

Norfolk

Primary Secondary Body

P10 S1 Breast

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Kelly et al. Owls, were similar to the Norfolk Eagle Owl values, or slightly more 13C-rich. The Dutch and (in particular) the Norwegian feather samples appear to show a positive relationship between δ13C and δ2H, which could be indicative of a marine influence in the signature of the feathers. The δ 15 N values of feathers from the Norfolk Eagle Owl ranged from +8.3 to +11.5‰. Most other groupings lie in the same δ15N range, with the exception of one of the Tawny Owl samples, which has feather δ15N values ranging from +2.6 to +5.3‰. It is most likely that this Tawny Owl was feeding at least one trophic level below the

other individuals in this study. The adult feathers from the Norfolk Eagle Owl were significantly enriched in 15N and slightly (but not significantly) enriched in 13C compared with the juvenile feathers. This is probably due to a change in the trophic level between the juvenile and adult stages. An alternative explanation is that a marine influence in the diet has resulted in enrichment of 15N and 13 C. However, this is unlikely since the natural prey of Eagle Owls is terrestrial.

Discussion

δ13C

The results from our analyses suggest that the two generations of feathers of the Norfolk Eagle Owl were -22.2 grown in different climatic -22.4 regions. P7 and S7–S14 (adult feathers) were clearly -22.6 enriched in deuterium rela-22.8 tive to the juvenile primaries -23.0 and secondaries. The δ2H of -23.2 the juvenile feathers lay -23.4 outside the range of values -23.6 found for the other Eagle Owls, of known origin, breast -23.8 measured here and would -24.0 juvenile-type adult-type perhaps be consistent with -24.2 an origin farther east in con-100.0 -90.0 -80.0 -70.0 -60.0 -50.0 -40.0 -30.0 -20.0 δ2H tinental Europe where the environmental δ2H is lower. Fig. 1. Dual isotope plot for feathers from the Norfolk Eagle Owl 2 The δ2H values of the adultBubo bubo.The closed circles ( H depleted) represent the juveniletype feathers and the open circles (2H enriched) represent the type feathers from the adult-type feathers. Norfolk Eagle Owl were similar to those of the Nor-15.0 wegian Eagle Owls and UK Norfolk (juvenile-type) Tawny Owls and showed a Norfolk (adult-type) -17.0 Netherlands marked difference from Norway those of the captive-bred -19.0 Tawny Owl (UK) Eagle Owls. In terms of Captive Eagle Owl carbon and nitrogen iso-21.0 topes, only the nitrogen isotope ratio differed -23.0 between the juvenile- and -25.0 adult-type feathers, indicating a marginal increase in -27.0 trophic level. -100.0 -80.0 -60.0 -40.0 -20.0 0.0 Owing to the limitations 2 δH of stable-isotope techniques Fig. 2. Dual carbon and hydrogen isotope plot showing the wide to pinpoint origins precisely, range of δ2H values for the sampled feathers from the Norfolk Eagle Owl Bubo bubo (juvenile- and adult-type feathers), Eagle Owls we cannot rule out the following alternative explanafrom the Netherlands and Norway,Tawny Owls Strix aluco from tions for the very low δ 2 H Norfolk and captive Eagle Owls from the UK. 218

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values of the first-generation feathers: 1. The Norfolk bird was captive-bred and had been fed on 2H-depleted food before escaping and subsequently living for a substantial period in the wild, with post-juvenile feathers reflecting its environment. 2. The bird was captivebred and had been fed 2H-depleted food for the first year before switching to a 2H-enriched diet in its second calendar-year, prior to escaping. 3. The bird was captivebred or wild-caught in an area where the δ2H value of precipitation is low and was then transported to East Anglia before escaping or being released. 4. The bird was wild but had hatched in a region of the UK with depleted local δ2H values. 5. Physiological differences between the juvenile and adult stage result in differences in the way δ 2H 114. Eagle Owl Bubo bubo, Helsinki, Finland, November 2006. marked; consequently, explanation 3 is is incorporated into feathers (a growth unlikely (although illegal importation effect). remains a possibility). There is no evidence to suggest that Explanation 5 is not compelling. We can captive-bred birds in the UK are fed on 2Hthink of no reason why juvenile and adult depleted food, although the δ 2 H values stages may differ in the way δ2H is incorprecorded in the feathers of captive birds were orated into feathers, and it is extremely considerably lower than those of the other unlikely that annual changes in δ2H would be specimens. Most captive-bred Eagle Owls in as marked as the differences we observed the UK are fed on day-old chicks, sourced in between the juvenile- and adult-type feathers the UK (Gary Dickenson pers. comm.) and of the Norfolk bird. so are most likely to reflect δ2H values of UK We cannot rule out (and cannot test for) precipitation. Explanations 1 and 2 require explanation 4, that the bird hatched in the that the food fed to a captive-bred bird was wild in the UK in a region with low local δ2H sourced from raw materials derived from 2 values before moving to Norfolk. Certainly, areas with low δ H precipitation values. In published data suggest that δ 2H values in terms of explanation 3, Eagle Owls are listed northern Britain and Scandinavia are similar on Annex A of CITES, with trade strictly (Bearhop et al. 2005), while Newton et al. controlled, and birds legitimately involved in (2006) showed that resident Scottish trade are required to be permanently British Birds 103 • April 2010 • 213–222

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Markus Varesvuo

Eagle Owl provenance using stable isotopes

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Kelly et al. Bullfinches (subspecies pileata) had δ 2 H values similar to those of the juvenile-type feathers from the Norfolk Eagle Owl. The possibility exists, therefore, that this bird may have hatched in an area of Scotland with low local δ2H values (in the wild or, indeed, in captivity) before moving (or being moved) south to Norfolk. The juvenile-type feathers suggest that the Norfolk bird’s natal area was characterised by precipitation with very low δ2H values. Such conditions occur in Scandinavia, north-continental Europe and mid-continental Russia – where Eagle Owls are known to occur – but also in northern parts of the UK (Hobson et al. 2004; Bowen et al. 2005). For example, the δ2H values of the first-generation feathers from the Norfolk Eagle Owl were similar to those of Grey Partridges Perdix perdix and Eurasian Curlews Numenius arquata from Russia and of Fieldfares Turdus pilaris and Redwings Turdus iliacus from Finland (Hobson et al. 2004); but also similar to those of resident Scottish Bullfinches (Newton et al. 2006). Unfortunately, as discussed above, stable-isotope analysis is not sufficiently precise to identify the natal area of this bird and, in fact, the alternative explanations for the observed isotopic differences between the juvenile and adult-type feathers listed above illustrate well the limitations of the technique. The strongest objection to Eagle Owls appearing in the UK as natural vagrants appears to be their relatively sedentary behaviour and reluctance to cross large expanses of water (Melling et al. 2008). However, although ringing recoveries confirm that Eagle Owls are largely sedentary, they are clearly capable of moving long distances, at least over land, as the examples given at the beginning of this paper show. Indeed, the fact that young birds in Switzerland have been shown to move up to 480 km before settling prompted Aebischer et al. (2010) to call for transnational conservation efforts. Moreover, the Eagle Owl’s range has been spreading in western Europe, despite declines in many European countries (Hagemeijer & Blair 1997). Although there is no conclusive evidence of the species undertaking a major sea crossing, natural vagrancy may not be as unlikely as suggested by 220

Melling et al. (2008). In future, it may be possible to identify the origin of Eagle Owls genetically using microsatellite markers developed in a captive population used to reinforce the Eagle Owl in Sweden (Isaksson & Tegelstrom 2002). Until then, stable isotopes may provide further information on possible vagrants. We were unable to obtain samples from any of the Yorkshire Eagle Owls and it would be interesting to compare the δ 2H of Eagle Owls known to have been raised in the UK with those from continental Europe and captivebred birds. We recommend that isotopic values of feathers of Eagle Owls of unknown provenance discovered in Britain in future should be measured and compared with those of specimens of known provenance. Acknowledgments Thanks to Hugh Jansman, Centre for Ecosystem Studies, the Netherlands for providing samples; Roy Dennis, Duncan Halley and Nils Røv, Norwegian Institute for Nature Research, for providing samples from five Eagle Owl specimens from the museum at the Norwegian University of Science and Technology (NTNU) in Trondheim; Lee Walker from the Centre for Ecology and Hydrology for samples from an Eagle Owl (an escaped captive) from Bristol; and Gar y Dickenson for feathers from two captive-bred Eagle Owls from Wales. Thanks also go to Reijo Kakela for translating a paper on the moult of Eagle Owls and to Adam Grogan for useful discussions. Finally the authors would like to thank Stuar t Bearhop for helpful comments which greatly improved the manuscript. References Aebischer, A., Nyffeler, P., & Arlettaz, R. 2010.Widerange dispersal in juvenile Eagle Owls (Bubo bubo) across the European Alps calls for transnational conservation programmes. J. Orn. 151: 1–9. —, —, Koch, S., & Arlettaz, R. 2005. Jugenddispersion und Mortalität Schweizer Uhus Bubo bubo – ein aktueller Zwischebericht. Ornithologischer Anzeiger 44: 197–200. Bearhop, S., Fiedler,W., Furness, R.W.,Votier, S. C., Waldron, S., Newton, J., Bowen, G. J., Berthold, P., & Farnsworth, K. 2005. Assortative mating as a mechanism for rapid evolution of a migratory divide. Science 310: 502–504. Bowen, G. J.,Wassenaar, L., & Hobson, K. A. 2005. Global application of stable hydrogen and oxygen isotopes to wildlife forensics. Oecologia 142: 337–348. British Ornithologists’ Union (BOU). 1997. Records Committee: twenty-third report (July 1996). Ibis 139: 197–201. Cramp, S. (ed.) 1985. The Birds of the Western Palearctic. Vol. 4. OUP, Oxford. Dennis, R. 2005.The Eagle Owl has landed. BBC Wildlife 23 (13): 24–29. British Birds 103 • April 2010 • 213–222

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Eagle Owl provenance using stable isotopes Dudley, S. P., Gee, M., Kehoe, C., Melling,T. M., & the BOURC. 2006.The British List: a checklist of birds of Britain (7th edn). Ibis 148: 526–563. Farquhar, G. D., Henry, B. K., & Styles, J. M. 1997. A rapid on-line technique for determination of oxygen isotope composition of nitrogen-containing organic matter and water. Rapid Communications in Mass Spectrometry 11: 1554. Fox, A. D., & Bearhop, S. 2008.The use of stableisotope ratios in ornithology. Brit. Birds 101: 112–130. —, Christensen,T. K., Bearhop, S. B., & Newton, J. 2007. Using stable isotope analysis of differing feather tracts to identify moulting provenance of vagrant birds – a case study of Baikal Teal Anas formosa in Denmark. Ibis 149: 622–625. Hagemeijer,W. J. M., & Blair, M. J. 1997. The EBCC Atlas of Breeding Birds: their distribution and abundance. Poyser, London. Hamann, C. 2002. Uhu aus Schleswig-Holstein flog bis an die französische Atlantik-Küste. EulenWelt 2002: 24–25. Hobson, K. A., Bowen, G. J.,Wassenaar, L. I., Ferrand,Y., & Lormee, H. 2004. Using stable hydrogen and oxygen isotope measurements of feathers to infer geographical origins of migrating European birds. Oecologia 141: 477–488. Holling, M., & the Rare Breeding Birds Panel. 2007. Non-native breeding birds in the United Kingdom in 2003, 2004 and 2005. Brit. Birds 100: 638–649. Isaksson, M., & Tegelstrom, H. 2002. Characterization of polymorphic microsatellite markers in a captive population of the Eagle Owl (Bubo bubo) used for supportive breeding. Molecular Ecology Notes 2: 91–93. Kelly, A.,Thompson, R., & Newton, J. 2008. Stable hydrogen isotope analysis as a method to identify illegally trapped songbirds. Science and Justice 48: 67–70.

Kornexl, B. E., Gehre, M., Höfling, R., & Werner, R. A. 1999. On-line 18O measurement of organic and inorganic substances. Rapid Communications in Mass Spectrometry 13: 1685–1693. Melling,T., Dudley, S., & Doherty, P. 2008.The Eagle Owl in Britain. Brit. Birds 101: 478–490. Neto, J. M., Newton, J., Gosler, A. G., & Perrins, C. M. 2006. Using stable isotope analysis to determine the winter moult extent in migratory birds: the complex moult of Savi’s Warblers. J. Avian Biol. 37: 117–124. Newton, I., Hobson, K. A., Fox, A. D., & Marquiss, M. 2006. An investigation into the provenance of Northern Bullfinches Pyrrhula p. pyrrhula found in winter in Scotland and Denmark. J. Avian Biol. 37: 431–435. Niiranen, S., & Haapala, J. 1987. Huuhkajan iän määrittäminen. Lintumies 20: 112–116. Rubenstein, D. R., & Hobson, K. A. 2004. From birds to butterflies: animal movement patterns and stable isotopes. Trends in Ecology and Evolution 19: 256–263. Snow, D.W., & Perrins, C. M. (eds.) 1998. The Birds of the Western Palearctic. Concise edn. OUP, Oxford. Stewart, J. R. 2007.The fossil and archaeological record of the Eagle Owl in Britain. Brit. Birds 100: 481–486. Wassenaar, L. I. 2008. An introduction to light stable isotopes for use in terrestrial animal migration studies. In: Hobson, K. A., & Wassenaar, L. I. (eds.), Tracking Animal Migration with Stable Isotopes. Elsevier, Amsterdam. — & Hobson, K. A. 2003. Comparative equilibration and online technique for determination of nonexchangeable hydrogen of keratins for use in animal migration studies. Isotopes in Environmental Health Studies 39: 211–217. Wunder, M. B., Kester, C. L., Fritz, L. K., & Rye, R. O. 2005. A test of geographic assignment using isotopic tracers in feathers of known origin. Oecologia 144: 607–617.

Andrew Kelly, RSPCA Stapeley Grange Wildlife Centre, London Road, Stapeley, Nantwich, Cheshire CW5 7JW; and School of Biological Sciences, Medical Biology Centre, Queen’s University Belfast, 97 Lisburn Road, Belfast BT9 7BL (correspondence address) Kevin Leighton, RSPCA East Winch Wildlife Centre, East Winch, Norfolk PE32 1NR Jason Newton, NERC Life Sciences Mass Spectrometry Facility, Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride G75 0QF

Appendix 1. SI preparation and analysis Hydrogen/oxygen isotope measurements Feathers were washed in 2:1 chloroform:methanol and dried at room temperature under a fume hood. A small section of mass 0.6–0.8 mg was clipped from the end of all feathers. In the case of the large primaries, small sections were cut from the tip, middle and base. In each case, the sample was weighed into individual silver capsules for hydrogen and oxygen isotope analysis. Isotope ratios were measured via continuous-flow stable-isotope mass spectrometry (CF-IRMS), using a Costech ECS 4010 elemental analyser in oxygen mode with high-temperature induction furnace (HTG-02) interfaced with a ThermoFisher Scientific Delta V Plus isotope ratio mass spectrometer, at the East Kilbride node of the NERC Life Sciences Mass Spectrometry Facility (Scottish Universities Environmental Research Centre). Repeat analyses of keratin standards incorporated into each hydrogen sample run showed that δ2H is measured with an accuracy and precision of ±2‰. Keratin standards CFS (chicken British Birds 103 • April 2010 • 213–222

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Kelly et al. feather), BWB-II (Bowhead Whale Balaena mysticetus baleen) (Wassenaar 2008) in conjunction with an internal standard ISB (Icelandic Kittiwake Rissa tridactyla feather) were used to correct samples for isotopic exchange between labile hydrogen in feathers and ambient water vapour in the laboratory using a comparative equilibration method (Wassenaar & Hobson 2003). The δ18O values of samples were compared to those of the reference materials IAEA CH6 (sucrose, Farquhar et al. 1997, Kornexl et al. 1999) and IAEA 601 and 602 (benzoic acid), though we recognise that the samples here are 18O-poor with respect to the standards used.

Carbon/nitrogen measurements Sections of the tips of all cleaned feathers were cut and transferred into 3 x 5-mm tin capsules, which were then measured by CF-IRMS, using a Costech ECS 4010 elemental analyser in CHNS mode interfaced with a ThermoFisher Scientific Delta V Plus isotope ratio mass spectrometer, at the East Kilbride node of the NERC LSMSF. Samples were measured against internal standards gelatin and two alanines with disparate carbon and nitrogen stable-isotope ratios. Long-term reproducibility is around 0.2‰ for d15N and 0.1‰ for δ13C. Stable-isotope ratios are expressed as the normalised ratio of the sample to a primary international standard, in parts per thousand (per mil, ‰): δX = [(Rsample /Rstandard) – 1] x 1,000 where Rsample and Rstandard are the ratios of heavy to light isotopes for the sample and the standard respectively. Rstandard for both d2H and d18O is Standard Mean Ocean Water (SMOW). Rstandard for δ13C is the Pee Dee Belemnite (PDB) and that for d15N is atmospheric nitrogen (AIR).

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The breeding population of Northern Wheatears at Clee Hill, Shropshire, 1998–2009 Dave Fulton Abstract The breeding population of Northern Wheatears Oenanthe oenanthe at Clee Hill, Shropshire, has been monitored since 1998 as part of the BTO Retrapping Adults for Survival project. Aspects of breeding biology, including laying dates, clutch size and brood size are presented, together with estimates of the return rate of adult birds.There is some evidence that the local population may be declining, with 2009 being a particularly poor year; this may reflect a combination of the national population trend and perhaps deterioration in the habitat for Wheatears in the study area. his short paper describes a study of the breeding population of Northern Wheatears Oenanthe oenanthe at Clee Hill, Shropshire, which was instigated in response to the Retrapping Adults for Survival (RAS) project set up by the BTO in 1998 to encourage ringers to collect highquality information on survival rates. Prior to 1998, Chelmarsh Ringing Group had been locating Wheatear nests and ringing pulli at

Clee Hill, but from 1998 onwards adults have also been trapped and ringed.

Study area and methods The study area covers some 700 ha of upland common land (at an altitude of some 400–500 m) in southern Shropshire. Since the latter part of the nineteenth century, Dhustone (dolerite), a hard volcanic rock used in road construction, has been quarried 223

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Fulton The majority of nests are found by watching the adults carrying food back to their chicks. This is generally done from the cover of a vehicle, when observers are almost invisible and can be within 10 m of the nest without disturbing the Wheatears. Adults are much more reluctant to return when observers are on foot. Most of the area is accessible by car, although this is becoming increasingly difficult as tracks are gradually being blocked to deter boy racers on quad bikes and in 4x4s. The same nest-sites are often used year after year, mostly by a different pair (although one member of the previous pairing may often be involved – very few pairs remain together in consecutive years). A new nest is always constructed alongside the old one, however, and up to five different nests have been found under favoured rocks. To minimise disturbance and the possibility of adults deserting the brood, chicks are not ringed until they are at least six days old. After a week or so, the adults are surprisingly tolerant of disturbance; on one occasion, members of the ringing group arrived to ring a brood of nine-dayold chicks and disturbed a Badger Meles meles, which had dug up the entire site. Fearing the worst, we looked inside what was now a huge cavern to find six terrified young Wheatears cow115 & 116. The study site at Clee Hill, Shropshire, May 2009.

Dave Fulton

from the area. Much of the local landscape has been affected by the quarrying industry and the area is littered with derelict buildings and redundant quarries, while rocks and scree habitat are plentiful. Sheep graze most of the area and one large quarry is still operational. The terrain is ideal for breeding Wheatears, which nest in rock piles, under large rocks, in drystone walls, under the concrete slabs of derelict buildings and occasionally in rabbit burrows. Surprisingly, some prefer to nest within the busy working quarry, despite having to travel farther to obtain food on the surrounding grassy slopes than birds elsewhere in the study area.

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Northern Wheatears in Shropshire for both Skokholm, Pembrokeshire, and Dungeness, Kent (Conder 1989). It is noticeably later than that for Skokholm, where laying begins in mid April and peaks in early May; this presumably reflects the lower minimum temperatures of the upland Shropshire study area in the weeks leading up to egg-laying. Mean clutch size varied between 5.03 and 6.12 in the 12 years at Clee Hill, with an overall mean of 5.42 (national mean 5.45, n=470; Skokholm mean 5.7, n=131; Dungeness mean 5.3, n=97; http://blx1.bto.org/ birdfacts/results/bob11460.htm, Conder 1989). Mean brood size varied annually between 4.43 and 5.67, with an overall mean of 5.06 (national mean 4.97, n=???; Skokholm mean 4.9, n=184; Dungeness 4.7, n=83). At Clee Hill, both parameters showed a slight but not significant downward trend across the 12 years. Published literature implies that Wheatears rather commonly raise two broods. For example, in Conder’s study of the birds on Skokholm, he found that 47% of the Wheatear pairs during 1948–53 laid second clutches (Conder 1989). At Clee Hill, second broods appear to be the exception. In 1998, one pair raised two broods from the same nest (six and two young fledged, respectively); in 2002, two pairs were doublebrooded, one using the same nest (six and four young fledged, respectively), the other making a new nest (outcome of second nest not known); and in 2008 a pair raised a

ering at the back. We spent half an hour rebuilding the site, remaking the nest and pulling in heavy boulders around the outside to deter the Badger’s return. Within an hour of the new nest being completed, both parents resumed feeding duties and the young fledged successfully a week later. Initially, walk-in (Potter) traps were used to catch adults but spring traps baited with mealworms have proved much more effective. Traps are placed near the nest entrance and are normally successful within 10–15 minutes. Adults are trapped only when they have young more than three days old since the adults may stay away from the nest for up to an hour after being caught. Adults are colour-ringed, with a colour representing the year of ringing above the BTO metal ring on the left leg, plus two other colours on the right leg.

Results and discussion Breeding biology Between 1998 and 2009, a total of 505 Wheatear nests were found in the study area, of which 297 were used to analyse timing of breeding, clutch size, brood size, etc. (only those for which the contents could be checked accurately were used). These include replacement clutches and a few second broods (see below). First-egg date varied between 1st May and 8th May, with a mean of 5th May and no obvious trend in the data. Interestingly, timing of breeding is later than that reported

Table 1. Breeding data from a population of Northern Wheatears Oenanthe oenanthe at Clee Hill, Shropshire, 1998–2009. Note that ‘nests used’ denotes the number of nests where contents could be checked accurately, and this figure therefore provides sample size for clutch size and brood size. 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

total/ mean

nests found

505

nests used

297

first-egg date

7th 4th 6th 6th 3rd 5th 2nd 1st 7th 4th 8th 5th May May May May May May May May May May May May

eggs laid

225

clutch size

5.77 5.38 5.55 5.31 5.03 5.23 6.12 5.77 5.18 5.15 5.07 5.38

young hatched 221

199 185

111 104

138 127

146 138

115 104

104 90

173 162

145 139

139 131

71 62

43 41

brood size

5.67 5.00 5.20 4.88 4.76 4.73 5.29 5.40 4.96 4.85 4.43 5.13

pulli ringed (all nests)

222

184

119

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148

106

159

150

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5.42 5.06

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Fulton

John Robinson

Site fidelity During the 12 years of fieldwork carried out so far, it became clear that marked adults return in subsequent years close to the previous year’s nest, while first-years disperse farther from their natal site. To investigate this further, the distance between nesting attempts in different years for the same individual birds was measured, using Google Earth mapping technology (table 2). These results showed clearly that, as expected, the breeding dispersal of adults was less than 117. Colour-ringed female Northern Wheatear Oenanthe the natal dispersal of young oenanthe in the Clee Hill study area. birds. second brood of three chicks (two eggs were There is, so far, no evidence from ringing infertile), after a disastrous first breeding returns or sightings of colour-ringed birds attempt where just one chick hatched and that Clee Hill Wheatears move to other five eggs were infertile. These were the only breeding locations. instances of true double broods in the 505 nests found. Adult survival There were very few instances in which Between 1998 and 2009, a total of 156 adult the same pair remained together in consecumales and 204 adult females were trapped tive years, and new partners were the norm. and colour-ringed. Tables 3 & 4 present the This appears not to be survival-related; there resighting data for these. are lots of examples where the male and As suggested by the name, the RAS project female from a pair both returned the folwas set up primarily to collect more informalowing year but bred with a new partner (e.g. tion on the survival rates of adult birds. three pairs in 2008, eight pairs in 2007). Just Complex calculations of survival rates are eight instances of a pair bond surviving for beyond the scope of Chelmarsh Ringing two consecutive seasons were recorded Group so the analysis presented here is very during the twelve study years. On three occabasic, showing the number of birds ringed sions, once in 1999 and twice (involving two each year and the number of individuals in different males) in 2006, a male paired simulthat cohort that were seen in subsequent taneously with two females, and helped to years (return rate). This of course takes no raise each brood. No instances of adults account of any emigration from the site (see paired with their offspring were found in the above), which any calculation of survival rate 12 seasons. would need to consider. Note that first-year Table 2. Distance between nesting attempts in different years according to age and sex classes (‘1Y’ refers to those ringed as chicks in one year, and observed as breeders in the study area in the subsequent year). Adult males No. observed breeding in consecutive seasons Mean distance between breeding attempts (adults) or between natal site and first breeding attempt (1Y)

226

Adult females

1Y males

1Y females

250 m

341 m

1,041 m

1,013 m

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Northern Wheatears in Shropshire Table 3. Resighting rates for male Northern Wheatears Oenanthe oenanthe at Clee Hill, Shropshire, 1998–2009. Same bird resighted after Year ringed

No. ringed

1 yr

2 yr

3 yr

4 yr

5 yr

6 yr

7 yr

8 yr

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

20 13 18 7 13 6 10 21 15 20 13

3 5 7 2 8 4 4 12 5 3 5

2 1 5 1 3 4 1 6 3 7 -

1 0 4 0 3 1 1 0 1 -

0 0 2 0 2 0 0 0 -

0 0 1 0 1 0 0 -

0 0 0 0 1 0 -

0 0 0 0 0 -

0 0 0 0 -

Totals Totals to 07 Totals to 06 Totals to 05 Totals to 04 Totals to 03 Totals to 02 Totals to 01

156 143 123 108 87 77 71 58

% return rate

33 11 4 2 1 0 0 37.2

23.1

8.9

3.7

2.3

1.3

Table 4. Resighting rates for female Northern Wheatears Oenanthe oenanthe at Clee Hill, Shropshire, 1998–2009. Same bird resighted after Year ringed

No. ringed

1 yr

2 yr

3 yr

4 yr

5 yr

6 yr

7 yr

8 yr

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

24 19 16 12 13 15 17 34 25 20 9

3 1 7 4 4 2 10 10 10 5 2

2 0 3 1 3 1 1 6 5 4 -

1 0 3 1 3 1 0 1 3 -

0 0 0 1 2 1 0 0 -

0 0 0 1 1 0 0 -

0 0 0 0 0 0 -

0 0 0 0 0 -

0 0 0 0 -

Totals Totals to 07 Totals to 06 Totals to 05 Totals to 04 Totals to 03 Totals to 02 Totals to 01

204 195 175 150 116 99 84 71

% return rate

26 13 4 2 0 0 0 28.4

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7.4

2.7

1.7

0 227

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Fulton birds, ringed the previous year as pulli, are not colour-ringed and must be trapped as breeding birds to be fitted with colour rings and added to this analysis (first-years are easy to trap at the nest, however, so not many are missed). The tables assume that when first trapped the birds were in their first summer; however, 25% of those trapped were aged as a second-summer or older, so a quarter of these birds survived at least one additional year than shown here. The Clee Hill data suggest that full-grown Wheatears are unlikely to return for more than six years. The data also suggest that males have a slightly higher return rate than females, which could be related to the extra stress of the breeding cycle on females (which includes taking on the majority of chickfeeding duties). One exceptional male was first ringed as a pullus on 28th May 1995 and retrapped on 31st May 2003; this individual currently holds the BTO longevity record for this species, of eight years and three days (Coiffait et al. 2008).

Local movements and migrations Considering the number of birds ringed, and the fact that most adults are colour-ringed, the number of controls/resightings outside the study area is extremely poor. Two pulli have been controlled outside Shropshire: one ringed on 29th May 1997 was controlled in Beni Frassen, Morocco, on 16th September 1998; another, ringed on 22nd May 2002, was controlled in Devon on 21st March 2006. Finally, an adult male trapped at Clee Hill on 22nd May 2005 was controlled in Hampshire the following spring, on 25th March 2006.

Long-term prospects for the Wheatears at Clee Hill The number of nests found in 2009 was an all-time low for the site, and any further decline in numbers will ring alarm bells for

the long-term sustainability of the population. The 2010 season is eagerly awaited, but it is feared that this recent decline may be linked to habitat changes in the Clee Hill area. Although a large part should remain untouched, recent changes in farming, affected in particular by the nature and availability of subsidies, may reduce the number of sheep grazing the area. Wheatears feed on the short swards produced by sheep grazing, and this is an essential component of the local habitat for this breeding population. In addition, when quarried seams are finally obsolete, the quarry company is under contract to fill in and return the land to ‘normal’. In practice, this means levelling the ground and sowing coarse, quick-growing grass. This generally remains ungrazed by sheep, while rocks and other ‘untidy’ potential Wheatear nesting areas are cleared away, all of which creates pressure on the Wheatear population at the site. A national decline in Wheatear numbers should also be borne in mind. Breeding Bird Survey figures for the UK as a whole during 1995–2007 show a decline of 11%, and for the same period there is a 24% decline in Wales. As well as local habitat changes, the national population trend (which may reflect factors operating on the wintering grounds and at migration stopovers) may be implicated in the changes observed. Acknowledgments Par ticular thanks are due to Dave Bastin, Tony Crossman and Joe Jordan, fellow member s of Chelmarsh Ringing Group, who have been stalwar t helpers in collecting the data presented here. References Coiffait, L., Clark, J. A., Robinson, R. A., Blackburn, J. R., Griffin, B. M., Risely, K., Grantham, M. J., Marchant, J. H., Girling,T., & Barber, L. 2008. Bird ringing in Britain and Ireland in 2006. Ringing & Migration 24: 15–79. Conder, P. 1989. The Wheatear. Christopher Helm, London.

Dave Fulton, 6 Hazelwells Road, Highley, Shropshire WV16 6DJ

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Conservation Priority Species

The decline of the Ring Ouzel in Britain

Ben Green

Innes Sim, Chris Rollie, David Arthur, Stuart Benn, Helen Booker, Vic Fairbrother, Mick Green, Ken Hutchinson, Sonja Ludwig, Mike Nicoll, Ian Poxton, Graham Rebecca, Leo Smith, Andrew Stanbury and Pete Wilson

Abstract The Ring Ouzel Turdus torquatus is a Red-listed, UK Biodiversity Action Plan priority species in Britain because of steep declines in breeding numbers over the past 25 years. Data from several monitoring projects, from across much of the species’ British range, show that widespread declines continue. Recent studies aimed at understanding these declines are reviewed, and suggest that low firstyear, and possibly adult, survival may be the main demographic mechanism driving the decline. The research priorities are now to identify the factors affecting survival, determine where these factors are operating, and find management solutions. © British Birds 103 • April 2010 • 229–239

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Sim et al. (both adults and larvae) (Flegg & Glue 1975; Durman 1977; Poxton 1986; Appleyard 1994; Tyler & Green 1994; Arthur & White 2001; Burfield 2002a; Sim et al. 2008). Between July and September, when adults undergo a complete post-breeding moult, and juveniles a partial moult, before they migrate, the diet is dominated by berries such as Bilberry Vaccinium myrtillus, Crowberry Empetrum nigrum and Rowan Sorbus aucuparia (Cramp 1988). Most British breeders have departed by late September, and reach the wintering grounds from mid October onwards. Winter diet is apparently dominated by Juniper berries, especially those of Prickly Juniper Juniperus oxycedrus and Phoenician Juniper J. phoenicea (Arthur et al. 2000; Ellis 2003; Ryall & Briggs 2006), although Zamora (1990) confirmed that arthropods supplement the diet in Spain. The birds return north from late February (Cramp 1988). Breeding populations in Fennoscandia and central and southern Europe are generally considered to be stable, but comprehensive monitoring data are lacking in many areas (Tucker & Heath 1994; Janiga & Poxton 1997; BirdLife International 2004). However, in parts of Switzerland, recent range contraction to higher altitudes has been recorded and this has been linked to warmer summers (Schmid et al. 1998; Mattes et al. 2005). This trend is predicted to continue, with a climate-induced decrease in suitable habitat shifting the predicted range of the Ring Ouzel by up to 440 m higher by 2070 (von dem Bussche et al. 2008). The British breeding population of Ring Ouzels has been in long-term decline, however. In the nineteenth century the species was widespread, with breeding records as far north as Orkney and perhaps as far south as Surrey, Kent and Essex (Holloway 1996). The decline appears to have begun in the twentieth century, and Baxter & Rintoul (1953) reported 118. Male Ring Ouzel Turdus torquatus, Cairngorms, May 2006.

he Ring Ouzel Turdus torquatus breeds in mountainous regions throughout Europe, and in southwest Asia. Three races are recognised: nominate torquatus breeds in Britain & Ireland and Fennoscandia, and winters in southern Spain and northwest Africa, especially in the Atlas Mountains of Morocco and Algeria; the central and southern European race T. t. alpestris breeds in central and southern Europe and winters in the south of the breeding range or in northwest Africa, thus largely overlapping with the winter range of nominate torquatus; and the eastern race T. t. amicorum breeds in the mountains of southwest Asia, east to northern Iran, and is thought to winter in Iran and southern Turkmenistan (Cramp 1988; Janiga & Poxton 1997). In Britain the Ring Ouzel is primarily a bird of the uplands, breeding mainly in steep-sided valleys, on crags and in gullies, from near sea level in the far north of Scotland up to 1,200 m in the Cairngorms (Cramp 1988; Gibbons et al. 1993; Rollie 2007). The breeding season stretches from mid April to mid July; pairs commonly rear two broods, and nests are located on or close to the ground, in vegetation (typically Heather Calluna vulgaris), in a crevice or, rarely, in a tree. Mean clutch size is 3.9–4.2 and mean fledged brood size is 3.5–3.8. Young are fed an invertebrate diet consisting mainly of earthworms (Lumbricidae), leatherjacket (Tipulidae) larvae and beetles

Andy Hay (rspb-images.com)

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The decline of the Ring Ouzel in Britain large decreases in parts of Scotland between 1900 and 1950. A 27% reduction in the British breeding range was apparent between the 1968–72 and 1988–91 national atlases (Sharrock 1976; Gibbons et al. 1993), and these more recent losses of range were particularly marked in Scotland and Wales. The first national survey, in 1999, estimated the UK population at 6,157–7,549 pairs, with further range contraction and a probable 58% decline in population size since 1988–91 (Wotton et al. 2002). This led to the Ring Ouzel being Red-listed (owing to a decline of more than 50% over 25 years), and made a priority Biodiversity Action Plan species, in the UK (Gregory et al. 2002; www.ukbap.org.uk). In this paper we first examine population trend data from a number of monitoring projects from across the species’ British breeding range (fig. 1) to determine its current regional status, and whether there is evidence of any broad geographical variation in the observed trends. Second, we review the evidence for the causes of regional declines in Britain and identify priorities for future research to enable effective conservation measures to be implemented.

Fig. 1. Location of Ring Ouzel Turdus torquatus study areas in Britain.

Recent population trends Surveys in the different study areas (fig. 1) were carried out mainly by members of the Ring Ouzel Study Group (www.ringouzel. info), which promotes co-ordinated research and monitoring of Ring Ouzels in Britain. This helped to ensure consistency in the survey methods used, with only minor variations among the different study areas. Thus, in each year of coverage, each area was surveyed at least twice between mid April and the end of June. This involved walking slowly through the study area, usually on transects about 200 m apart, recording the number of territorial pairs (based upon nest-building activity, nests located, recently fledged young, pairs seen or territorial behaviour observed on more than one visit, and/or agitated behaviour consistent with an occupied nest). Surveys were not carried out during heavy rain or in strong winds. In Glen Clunie, Glen Effock, Glen Esk, the North York Moors and the Forest of Bowland, surveys were carried out approximately every two weeks, as part of more British Birds 103 • April 2010 • 229–239

intensive studies of breeding biology. Ring Ouzel song was played regularly (to elicit a response from territorial males) in Wales and the Northwest Highlands, to ensure comparability with the 1999 national survey (Wotton et al. 2002), which provided the baseline data in these areas. The different studies varied in the frequency of coverage during the respective study periods, ranging from some with annual (or near-annual) coverage to those providing two ‘snapshots’ only. The period covered by different studies also varied, extending across 27 years in Dartmoor but only six years in Glen Effock. The survey results show that declines were widespread and serious, with 13 of the 14 study areas showing a reduction in numbers (figs. 2 & 3). This included 11 areas in which the decline exceeded 50% (over periods of 7–27 years), and two in which the populations declined to extinction. Ring Ouzel numbers in ten tetrads (2 km x 2 km squares) in the Northwest Highlands declined by 70% during 1999–2007, and by 231

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Sim et al. Highlands, Glen Clunie, Glen Callater, Glen Esk and Glen Effock), southeast Scotland and northern England combined (Lammermuirs, Moorfoots, Pentlands, Forest of Bowland and North York Moors) and more southwest locations (Dartmoor, Exmoor, Long Mynd and Wales). However, there was no evidence for any significant geographical variation (F2,9 = 0.39, P = 0.68). The reasons for the population increase in Glen Effock are unknown, but may be linked to a recent rise in sheep grazing, which has increased the area of short grass (M. Nicoll pers. obs.), the favoured foraging habitat for Ring Ouzels during the nestling period (Burfield 2002a). Continued monitoring to determine future trends at Glen Effock, together with studies to identify the respective roles of survival, breeding success and immigration of breeding birds, is vital. Site-specific factors may also influence trends at some of the other study areas. For example, decreases in sheep grazing have 90 been noted in Glen Esk (with an 80 expected reduction 70 NW Highlands in areas of short Glen Callater 60 grass), while the Lammermuirs 50 decline to extincMoorfoots 40 tion of the small Pentlands 30 and isolated Long Wales 20 Mynd population Dartmoor was associated 10 Exmoor with increased nest 0 1975 1980 1985 1990 1995 2000 2005 2010 predation (Smith 2006). However, Fig. 2. Trends in Ring Ouzel Turdus torquatus numbers in Britain from the widespread periodic repeat surveys. and near-consis40 tent steep declines that have been 35 recorded in most 30 areas strongly Glen Clunie 25 suggest that largeGlen Esk scale factors are 20 Glen Effock affecting the N York Moors 15 British Ring Ouzel Long Mynd 10 population and Bowland 5 driving the observed national 0 1990 1994 1998 2002 2006 2010 population decline. territorial pairs

territorial pairs

83% in Glen Callater during 1998–2007. Three hill ranges (Lammermuirs, Moorfoots and Pentlands) in southeast Scotland showed declines of around 50% during 1985–2006, and numbers in 26 tetrads in Wales declined by 69% during 1999–2006. The Exmoor population declined from 13 pairs in 1993 to extinction in 2003–05, and numbers on Dartmoor fell by 63% during 1979–2006 (fig. 2). The Glen Clunie population declined by 67% during 1999–2009. In Glen Esk numbers fell by 41% during 1992–2009, but in the neighbouring Glen Effock they increased by 88% during 2002–08. There was a population decline of 44% in Rosedale, North York Moors, during 2002–09, and the Long Mynd population declined from 16 pairs in 1995 to extinction in 2004–09. Finally, in the Forest of Bowland, numbers declined by 68% during 1995–2009 (fig. 3). We compared the proportional decline between the Scottish Highlands (Northwest

Fig. 3. Trends in Ring Ouzel Turdus torquatus numbers from study areas in Britain surveyed regularly in recent years. Broken lines indicate missing data from some years. 232

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The decline of the Ring Ouzel in Britain Research into causes of declines

desertion was more likely at lower altitudes and where there was now lower Heather cover within both 200 m and 450 m of former nesting sites (Sim et al. 2007). In addition, the currently occupied nesting sites in the Moorfoots were more likely to have Heather or a Heather/grass mosaic within 100 m than were topographically suitable, but unoccupied, potential nesting sites. Together, these studies show that Ring Ouzel breeding distribution has contracted to sites at higher altitudes, with greater Heather cover and away from conifer plantations. They do not demonstrate whether such relationships are causal (for example, whether lower Heather cover around nests affects breeding success, or climate change is causing low-altitude sites to become unsuitable), or whether they simply reflect a contraction to preferred areas as the population declines because of other, unrelated, causes (such as reduced overwinter survival). However, declines have also been recorded in areas where Heather cover remains extensive around nesting sites and where there has been little or no afforestation (e.g. Glen Clunie, Glen Esk and Glen Callater). Further-

Innes Sim

A number of possible causes have been suggested to explain the decline of the British Ring Ouzel population but, until recently, little evidence has been available to assess which of these may be relevant, and at which stage of the life-cycle they may be operating. However, over the last decade a number of detailed studies have added considerably to our knowledge of Ring Ouzel ecology, habitat requirements and population dynamics. Two studies have examined factors associated with declines in breeding abundance, or the desertion of historically occupied breeding sites. First, analyses of data from across Scotland found that Ring Ouzels had contracted to steeper areas within an altitudinal range of 350–750 m, and away from coniferous forests and any associated potential impacts on adjacent moorlands (e.g. decreased grazing pressure on adjacent open ground, increased numbers of potential predators using the forests as cover and population fragmentation; Buchanan et al. 2003). Second, long-term data on the occupation of breeding sites in the Moorfoot Hills, between 1952–85 and 1998–2000, found that site

119. A typical Ring Ouzel Turdus torquatus nest-site in Britain, this one being on a heather-covered crag in Glen Clunie in May 2008. British Birds 103 • April 2010 • 229–239

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Sim et al. may be driving Ring Ouzel population declines, possibly through causing drier soil conditions, hence reducing earthworm availability, at the end of the breeding season and during the post-fledging period (Beale et al. 2006). However, preliminary findings from studies in 2007–08 on the foraging behaviour and survival of radio-tagged Ring Ouzel fledglings at Glen Clunie (Sim et al. in prep.) provide little evidence for unusually low survival during the post-fledging period. Indeed, Ring Ouzel survival rates there appear to compare favourably with those of similarsized passerines in Britain and the USA (Anders et al. 1997; Robinson et al. 2004; White et al. 2005; King et al. 2006; Schmidt et al. 2008). In addition, there was no evidence for any seasonal decline in either earthworm abundance or soil moisture levels, although 2007 was a very wet year and 2008 a fairly dry one. However, this study covered only two summers, and a longer run of data would be required to assess how local, national and global climatic variables may influence local Ring Ouzel productivity and survival. Long-term studies of breeding success and survival rates in declining populations can provide valuable insights into, and under-

Innes Sim

more, detailed studies have found that nest survival rates and overall breeding success in the Moorfoot Hills (an area with afforestation and historical declines in Heather cover) were similar to those in other areas where there has been little change in these aspects of the habitat (e.g. Glen Esk and Glen Clunie; Burfield 2002a; Sim et al. in prep.). Therefore, while such land-use changes have undoubtedly contributed to declines in some areas, they seem unlikely to be the major factor driving the overall declines. Another study investigated climate correlates of Ring Ouzel breeding success and population trends in northern Britain, to assess possible links between population decline and climate change (Beale et al. 2006). Population declines in the Moorfoot Hills followed years when British summer (June–August) weather was warm and moderately wet, and when spring rainfall in Morocco 24 months previously was high (suppressing Juniper flowering, and thus reducing berry production, with possible adverse consequences for subsequent overwinter survival of Ring Ouzels). Based upon the recent trends in these three weather variables, these relationships suggested that increases in British summer temperatures

120. Brood of four Ring Ouzels Turdus torquatus in a nest in Glen Clunie, July 2009. 234

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Mick Green

The decline of the Ring Ouzel in Britain

121. Wintering habitat for British Ring Ouzels Turdus torquatus: the juniper-clad slopes of the Atlas Mountains in Morocco.

standing of, the causes of decline. Such work has been undertaken in a joint Grampian Ringing Group/RSPB project on Ring Ouzels in Glen Clunie during 1998–2009. This glen was known to hold a relatively high-density population that was stable between 1991 and 1998 (Rebecca 2001), but which subsequently declined markedly during 1998–2009 (fig. 3). Over this period, changes in some aspects of breeding success have been detected (e.g. reduced mean brood size of first nests at fledging, from 3.8 to 3.4, owing to decreased nestling survival). However, this effect has been offset by a small increase in nest survival rate, so that there has been no decline in overall reproductive success (Sim et al. in prep.). Preliminary analyses of adult survival of Ring Ouzels in Glen Clunie suggest that it was low compared with similar species in Britain and North America (Savidge & Davis 1974; Nichols et al. 1981; Roth & Johnson 1993; Siriwardena et al. 1998; Porneluzi & Faaborg 1999; Bayne & Hobson 2002; Gardali et al. 2003). Although adult Ring Ouzel survival did not decline during the course of the study, return rates of first-year birds did decline, though whether this reflected higher mortality, higher dispersal away from the British Birds 103 • April 2010 • 229–239

natal areas, or both, is unknown. Since adult survival appears to be low compared with similar species, and given that population modelling (elasticity analysis) indicates that population growth rate is particularly sensitive to variation in first-year survival, this suggests that low survival may be a key driver of Ring Ouzel declines (Sim et al. in prep.). It is therefore important to identify the causes of poor survival. As a migrant, the Ring Ouzel is affected by factors acting on the breeding grounds, in overwintering areas and during migration, and this adds to the difficulties of identifying the causes of low survival. An analysis of the number of Ring Ouzel bird-days at British and Irish bird observatories in spring during 1970–98 found that numbers passing through western observatories (assumed to be mainly British breeding birds) declined significantly, whereas numbers passing through east-coast observatories (assumed to be mainly Fennoscandian breeders) did not (Burfield & Brooke 2005). If these assumptions are correct, this suggests that the causes of low survival could occur on the breeding grounds or on migration, because British and Fennoscandian birds have overlapping wintering ranges (Burfield 2002b); individuals of 235

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Sim et al. than Fennoscandian breeders in spring may be exposed to greater mortality risks from hunting. Furthermore, in autumn, British breeders probably migrate through France on a more westerly route than Fennoscandian breeders and are more likely to pass through southwest France, where ringing recoveries show that hunting pressure is particularly intense (Burfield 2001). Few studies of Ring Ouzels have been undertaken in their wintering areas, but in southern Spain the berries of Common J. communis and Phoenician Juniper were the most frequent food items (Zamora 1990; Jordano 1993). However, in Morocco’s Atlas Mountains, Phoenician (and to a lesser extent Prickly) Juniper berries were considered the most frequent food items (Arthur et al. 2000; Ellis 2003). Ryall & Briggs (2006) confirmed this preference for Phoenician Juniper, and noted that the Juniper woodlands used by Ring Ouzels were in a degraded and ageing state. Damage to trees from cutting, indicative of general levels of disturbance, appeared to be a stronger determinant of Ring Ouzel presence than did the number of berries (Ryall & Briggs 2006). In addition, Beale et al. (2006) provided some evidence that food availability in the wintering areas may affect survival, linking population declines in the Moorfoot Hills to levels of rainfall in the wintering areas (and hence Juniper berry abundance – see above).

Andy Hay (rspb-images.com)

both subspecies have been trapped at the same time and in the same nets in Morocco (Ellis 2003). The expected difference in migration route and timings of the two populations could expose them to different risks. In particular, although hunting of other thrush species is permitted under the Birds Directive in certain EU countries, particularly in the Mediterranean, the Ring Ouzel is not a legal quarry in any member state (OJEU 2010). However, there is a real risk that Ring Ouzels may be confused with other thrushes by hunters and shot in error. In general, the hunting season in France ends on 10th February but a number of species (including thrushes) may be legally hunted in some southern departments until 20th February (JORF 2009). Consequently, British-breeding Ring Ouzels passing through France earlier

Future research priorities

122. Male Ring Ouzel Turdus torquatus, Cairngorms, May 2006. 236

Research to date has identified a number of factors that may be involved in causing the decline of the British Ring Ouzel population, but suggests that low first-year, and possibly British Birds 103 • April 2010 • 229–239

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The decline of the Ring Ouzel in Britain adult, survival may be the critical demographic parameter driving this decline. The causes of low survival and whether these are operating on the breeding or wintering grounds, or on migration routes, remain unknown. Research that examines the factors affecting survival at all of these stages of the life-cycle is now urgently required. Designing and undertaking studies that measure survival during each of these stages, and which identify the main causes of mortality, represents a major challenge. However, recent advances in the miniaturisation of tracking devices, most notably geolocators (Fiedler 2009), mean that it is now possible to track birds the size of a Ring Ouzel through the full annual cycle, and this increases the feasibility of identifying the timing of migration and the location of the main stopover and wintering sites. Further work should also be encouraged on the British breeding grounds, to test experimentally the effect of habitat and management manipulations on breeding success and survival. Effective monitoring of the British breeding population remains challenging, with coverage by the Breeding Bird Survey (BBS) being inadequate to detect national trends. Recent increases in BBS coverage within the English uplands will help to improve this situation considerably, but the majority of the British population will remain poorly covered. However, the second national Ring Ouzel survey, scheduled for 2011, should provide information on national and regional population trends, and the results of the 2007–11 Atlas will shed light on changes in distribution. Outside Britain, further studies of Ring Ouzel ecology in the wintering areas would be valuable. Studies to establish the full wintering range of the British breeding population, and the extent and drivers (e.g. agriculture, development, drought, demand for firewood) of change in Juniper woodlands within this area will help to determine whether winter food supplies may be a critical issue. Determining whether large numbers of British birds are being killed on migration through France and Spain would similarly provide initial indications as to the role of hunting mortality. Finally, there is a need to improve our knowledge of trends British Birds 103 • April 2010 • 229–239

and, where relevant, the causes of declines in other European breeding populations. Many of these are very poorly studied and the trend data available are qualitative or semi-quantitative at best (Tucker & Heath 1994; Janiga & Poxton 1997; BirdLife International 2004). Priority countries for improved monitoring should include those with the largest populations (e.g. Romania, Austria, Norway and Russia) and those at the southern limit of the range and thus most vulnerable to climate change (e.g. Spain, Italy and Turkey). Acknowledgments We thank the members of the Ring Ouzel Study Group who contributed to the regional studies and landowners and tenants for co-operation with access. The Glen Clunie study was funded by RSPB, the Scottish Ornithologists’ Club, Scottish Natural Heritage and the Cairngorms National Park Authority. Surveys on Dartmoor and Exmoor were funded by Dartmoor and Exmoor National Par k Authorities, Natural England and Defence Estates. Ian Burfield, Murray Grant and Jeremy Wilson provided valuable comments on earlier drafts of the paper. References Anders, A. D., Dearborn, D. C., Faaborg, J., & Thompson, F. R. 1997. Juvenile survival in a population of neotropical migrant birds. Cons. Biol. 11: 698–707. Appleyard, I. 1994. Ring Ouzels of the Yorkshire Dales. Maney, Leeds. Arthur, D. S. C., & White, S. A. 2001. Numbers, distribution and breeding biology of Ring Ouzels in upper Glen Esk, 1992–98. Scott. Birds 22: 50–59. —, Ellis, P. R., Lawie, R. G., & Nicoll, M. 2000. Observations of wintering Ring Ouzels and their habitat in the High Atlas Mountains, Morocco. Scott. Birds 21: 109–115. Baxter, E.V., & Rintoul, L. J. 1953. The Birds of Scotland. Oliver & Boyd, Edinburgh. Bayne, E. M., & Hobson, K. A. 2002. Annual survival of adult American Redstarts and Ovenbirds in the southern Boreal forest. Wilson Bull. 114: 358–367. Beale, C. M., Burfield, I. J., Sim, I. M. W., Rebecca, G. W., Pearce-Higgins, J. W., & Grant, M. C. 2006. Climate change may account for the decline in British Ring Ouzels Turdus torquatus. J. Anim. Ecol. 75: 826–835. BirdLife International 2004. Birds in Europe: population estimates, trends and conservation status. BirdLife International (Conservation Series No. 12), Cambridge. Buchanan, G. M., Pearce-Higgins, J. W., Grant, M. C., & Whitfield, P. 2003. Correlates of the change in Ring Ouzel Turdus torquatus abundance in Scotland from 1988–91 to 1999. Bird Study 50: 97–105. Burfield, I. J. 2001. Ringed ouzels: where do they go in winter? Ringers’ Bull. 10: 58. — 2002a.The breeding ecology and conservation of the Ring Ouzel Turdus torquatus in Britain. Unpublished PhD thesis. University of Cambridge. — 2002b.The Ring Ouzel. In: Wernham, C.V.,Toms, M. P., Marchant, J. H., Clark, J. A., Siriwardena, G. M., & 237

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Sim et al. Baillie, S. R. (eds.), The Migration Atlas: movements of the birds of Britain & Ireland. Poyser, London. — & Brooke, M. de L. 2005.The decline of the Ring Ouzel Turdus torquatus in Britain: evidence from bird observatory data. Ringing & Migration 22: 199–204. Cramp, S. (ed.) 1988. The Birds of the Western Palearctic. Vol. 5. OUP, Oxford. Durman, R. F. 1977. Ring Ouzels in the Pentlands. Edinburgh Ringing Group Report 5: 24–27. Ellis, P. 2003. Ringing Ring Ouzels Turdus torquatus in Morocco.Tay Ringing Group Report 2001–03: 32–40. Fiedler, W. 2009. New technologies for monitoring bird migration and behaviour. Ringing & Migration 24: 175–179. Flegg, J. J. M., & Glue, D. E. 1975.The nesting of the Ring Ousel. Bird Study 22: 1–8. Gardali,T., Barton, D. C., White, J. D., & Geupel, G. 2003. Juvenile and adult survival of Swainson’s Thrush (Catharus ustulatus) in coastal California: annual estimates using capture-recapture analyses. Auk 120: 1188–1194. Gibbons, D. W., Reid, J. B., & Chapman, R. A. 1993. The New Atlas of Breeding Birds in Britain and Ireland: 1988–1991. Poyser, London. Gregory, R. D., Wilkinson, N. I., Noble, D. G., Robinson, J. A., Brown, A. F., Hughes, J., Procter, D. A., Gibbons, D. W., & Galbraith, C. A. 2002.The population status of birds in the United Kingdom, Channel Islands and Isle of Man: an analysis of conservation concern 2002–2007. Brit. Birds 95: 410–450. Holloway, S. 1996. The Historical Atlas of Breeding Birds in Britain and Ireland: 1875–1900. Poyser, London. Janiga, M., & Poxton, I. R. 1997.The Ring Ouzel. In: Hagemeijer, W. J. M., & Blair, M. J. (eds.), The EBCC Atlas of European Breeding Birds. Poyser, London. Jordano, P. 1993. Geographical ecology and variation of plant-seed disperser interactions: southern Spanish junipers and frugivorous thrushes. Vegetation 107–108: 85–104. JORF 2009. Arrêté du 19 janvier 2009 relatif aux dates de fermeture de la chasse aux oiseaux de passage et au gibier d’eau, hormis les limicoles et les oies. Journal officiel de la République française 17 (21 January 2009): 1321. www.legifrance.gouv.fr/affichTexte.do;jsessionid= FA9986F2437D0FC956C4C7EF3AEEF1C5. tpdjo09v_1?cidTexte=JORFTEXT000020128976& categorieLien=id King, D. I., Degraaf, R. M., Smith, M-L., & Buonaccorsi, J. P. 2006. Habitat selection and habitat-specific survival of fledgling Ovenbirds (Seiurus aurocapilla). J. Zool. 269: 414–421. Mattes, H., Maurizio, R., & Burkli, W. 2005. Die Vogelwelt im Oberengadin, Bergell und Puschlav. Schweizerische Vogelwarte, Sempach. Nichols, J. D., Noon, B. R., Stokes, S. L., & Hines, J. E. 1981. Remarks on the use of mark-recapture methodology in estimating avian population size. Studies in Avian Biology 6: 121–136. OJEU 2010. EC Directive 2009/147/EC of the European Parliament and of the Council of 30 November 2009 on the conservation of wild birds (codified version). Official Journal of the European Union L 20 (26 January 2010): 7–25. http://eurlex.europa.eu/LexUriServ/LexUriServ. do?uri=OJ:L:2010:020:0007:0025:EN:PDF 238

Porneluzi, P. A., & Faaborg, J. 1999. Season-long fecundity, survival, and viability of Ovenbirds in fragmented and unfragmented landscapes. Cons. Biol. 13: 1151–1161. Poxton, I. R. 1986. Breeding Ring Ouzels in the Pentland Hills. Scott. Birds 14: 44–48. Rebecca, G. W. 2001.The contrasting status of the Ring Ouzel in two areas of upper Deeside, north east Scotland, between 1991 and 1998. Scott. Birds 22: 9–19. Robinson, R. A., Green, R. E., Baillie, S. R., Peach, W. J., & Thomson, D. L. 2004. Demographic mechanisms of the population decline of the Song Thrush Turdus philomelos in Britain. J. Anim. Ecol. 73: 670–682. Rollie, C. 1997.The Ring Ouzel. In: Forrester, R. W., Andrews, I. J., McInerny, C. J., Murray, R. D., McGowan, R.Y., Zonfrillo, B., Betts, M. W., Jardine, D. C., & Grundy, D. S. (eds.), The Birds of Scotland. SOC, Aberlady. Roth, R. R., & Johnson, R. K. 1993. Long-term dynamics of a Wood Thrush population breeding in a forest fragment. Auk 110: 37–48. Ryall, C., & Briggs, K. 2006. Some factors affecting foraging and habitat of Ring Ouzels Turdus torquatus wintering in the Atlas Mountains of Morocco. Bull. African Bird Club 13: 17–31. Savidge, I. R., & Davis, D. E. 1974. Survival of some common passerines in a Pennsylvania woodlot. Bird-Banding 45: 152–155. Schmid, H., Luder, R., Naef-Daenzer, B., Graf, R., & Zbinden, N. 1998. Schweizer Brutvogelatlas. Verbreitung der Brutvögel in der Schweiz und im Fürstentum Liechtenstein 1993–1996. Schweizerische Vogelwarte, Sempach. Schmidt, K. A., Rush, S. A., & Ostfeld, R. S. 2008. Wood Thrush nest success and post-fledging survival across a temporal pulse of small mammal abundance in an oak forest. J. Anim. Ecol. 77: 830–837. Sharrock, J.T. R. (ed.) 1976. The Atlas of Breeding Birds in Britain & Ireland. Poyser, Calton. Sim, I. M. W., Rebecca, G. W., & Ludwig, S. C. 2008. Glen Clunie Ring Ouzel Breeding Ecology Project. North-East Scotland Bird Report 2006: 117–119. —, —, —, Grant, M. C., & Reid, J. M. (In prep.). Characterising demographic variation and contributions to population growth rate in a small, declining Ring Ouzel Turdus torquatus population. —, Burfield, I. J., Grant, M. C., Pearce-Higgins, J. W., & Brooke, M. de L. 2007.The role of habitat composition in determining breeding site occupancy in a declining Ring Ouzel Turdus torquatus population. Ibis 149: 374–385. Siriwardena, G. M., Baillie, S. R., & Wilson, J. D. 1998. Variation in the survival rates of some British passerines with respect to their population trends on farmland. Bird Study 45: 276–292. Smith, L. 2006. Shropshire Biodiversity Action Plan for Ring Ouzel. Shropshire Biodiversity Partnership. Tucker, G. M., & Heath, M. F. 1994. Birds in Europe: their conservation status. BirdLife International (Conservation Series No. 3), Cambridge. Tyler, S. J., & Green, M. 1994.The status and breeding ecology of Ring Ouzels Turdus torquatus in Wales with reference to soil acidity. Welsh Bird Report 7: 78–79. von dem Bussche, J., Spaar, R., Schmid, H., & Schroder, British Birds 103 • April 2010 • 229–239

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The decline of the Ring Ouzel in Britain B. 2008. Modelling the recent and future spatial distribution of the Ring Ouzel (Turdus torquatus) and Blackbird (T. merula) in Switzerland. J. Ornithol. 149: 529–544. White, J. D., Gardali,T.,Thompson, F. R., & Faaborg, J. 2005. Resource selection by juvenile Swainson’s Thrushes during the postfledging period.

Condor 107: 388–401. Wotton, S. R., Langston, R. H., & Gregory, R. D. 2002. The breeding status of the Ring Ouzel Turdus torquatus in the UK in 1999. Bird Study 49: 26–34. Zamora, R. 1990.The fruit diet of Ring Ouzels (Turdus torquatus) wintering in the Sierra Nevada. Alauda 58: 67–70.

Innes Sim, RSPB Scotland, Dunedin House, 25 Ravelston Terrace, Edinburgh EH4 3TP Chris Rollie, RSPB Scotland, The Old School, Crossmichael, Castle Douglas DG7 3UW David Arthur, Panmure Cottage, 1 Tennis Road, Carnoustie DD7 6HH Stuart Benn, RSPB Scotland, Etive House, Beechwood Park, Inverness IV2 3BW Helen Booker, RSPB, Keble House, Southernhay Gardens, Exeter EX1 1NT Vic Fairbrother, 8 Whitby Avenue, Guisborough, Cleveland TS14 7AP Mick Green, Ecology Matters Ltd, Bronhaul, Pentrebach, Talybont SY24 5EH Ken Hutchinson, White Gate Cottage, Church Lane, Thornton le Dale, North Yorkshire YO18 7QL Sonja Ludwig, c/o RSPB Scotland, Dunedin House, 25 Ravelston Terrace, Edinburgh EH4 3TP Mike Nicoll, Dundee Museum, Dundee, Tayside DD1 1DA Ian Poxton, 217 Newbattle Abbey Crescent, Dalkeith, Midlothian EH22 3LU Graham Rebecca, RSPB Scotland, 10 Albyn Terrace, Aberdeen AB10 1YP Leo Smith, 8 Welsh Street Gardens, Bishops Castle, Shropshire SY9 5BH Andrew Stanbury, RSPB, The Lodge, Sandy, Bedfordshire SG19 2DL Pete Wilson, RSPB, United Utilities Bowland Estate Office, Stocks Boardhouse, Slaidburn, Clitheroe, Lancashire BB7 3AQ

Atlas 2007–11 update At the halfway stage of breedingseason fieldwork for Bird Atlas 2007–11, a provisional map showing the distribution of the Ring Ouzel is available. The level of breeding evidence recorded so far is shown by the size of the dot, which indicates possible (small), probable (medium) and confirmed (large) breeding. Fieldwork in April–July 2008 and 2009 covered much of the core range of the Ring Ouzel, although some remote or difficult-to-access 10-km squares may not have been visited yet. Compared with the 1988–91 Breeding Atlas, the provisional map suggests further range contraction across all breeding areas in Britain & Ireland. If you have any records from 2008 or 2009 not shown here, please submit them as soon as possible. Fieldwork for the third breeding season started on 1st April and all records of Ring Ouzels in breeding habitat are welcomed. Records can be submitted online at www.birdatlas.net or by requesting paper forms from the BTO (tel. 01842 750050). British Birds 103 • April 2010 • 229–239

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Letters Eskimo Curlews I very much enjoyed Tim Melling’s thorough paper on the Eskimo Curlew Numenius borealis in Britain (Brit. Birds 103: 80–92). However, I would like to comment on two particular issues raised in the article. Firstly, I was surprised by the repeated assertion that Audubon saw the Eskimo Curlew only once, off South Carolina. In fact, he saw the species on many occasions and in considerable numbers. On 6th June 1833, Audubon and five companions left Eastport, Maine, on the schooner Ripley, spending the summer in Labrador and returning on 31st August. The expedition’s highlights were the discovery of Lincoln’s Sparrow Melospiza lincolnii and the recording of large numbers of Eskimo Curlews (Townsend 1918). In the Ornithological Biography (Audubon 1831–1839) which accompanied Audubon’s monumental Birds of America, there is a thorough first-hand account of these observations. The following is but a brief extract: ‘On the 29th of July, 1833, during a thick fog, the Esquimaux Curlews made their first appearance in Labrador, near the harbour of Brag d’Or. They evidently came from the north, and arrived in such dense flocks as to remind me of the Passenger Pigeons… For more than a week we had been looking for them, as was every fisherman in the harbour, these birds being considered there, as indeed they are, great delicacies. The birds at length came, flock after flock, passed close round our vessel, and directed their course toward the sterile mountainous tracts in the neighbourhood; and as soon as the sun’s rays had dispersed the fogs that hung over the land, our whole party went off in search of them. ‘I was not long in discovering that their stay on this coast was occasioned solely by the density of the mists and the heavy gales that

already gave intimation of the approaching close of the summer; for whenever the weather cleared up a little, thousands of them set off and steered in a straight course across the broad Gulf of St Lawrence. On the contrary, when the wind was high, and the fogs thick, they flew swiftly and low over the rocky surface of the country, as if bewildered. Wherever there was a spot that seemed likely to afford a supply of food, there the Curlews abounded, and were easily approached. By the 12th of August, however, they had all left the country.’ Secondly, the paper refers to the sweeping changes overtaking the American prairies as an additional factor in the demise of the Eskimo Curlew. Changes to grazing and burning regimes and the extinction of the Rocky Mountain Locust Melanopus spretus are rightly highlighted but perhaps the most important factor in the transformation of the grassland ecosystem was ploughing. The Eskimo Curlews favoured the tallgrass prairie zone of eastern Oklahoma, Kansas and Nebraska and western Missouri and Iowa (Johnsgard 1980) but by 1870 the settlement frontier had already crossed these rich grasslands and reached as far west as the 98th meridian, the threshold of more arid country. Equipped with John Deere’s new steel plough, settlers tore up the sod with enthusiasm and by 1890 most of the eastern tallgrass was gone (Webb 1931). References Audubon, J. J. 1831–1839. Ornithological Biography. Black, Edinburgh. Johnsgard, P. A. 1980. Where Have All the Curlews Gone? University of Nebraska, Lincoln. http://digitalcommons.unl.edu/biosciornithology/23 Townsend, C.W. 1918. In Audubon’s Labrador. Houghton Mifflin, Boston. Webb,W. P. 1931. The Great Plains. Grosset & Dunlap, New York.

Andy Stoddart, 7 Elsden Close, Holt, Norfolk NR25 6JW

Eagle Owls in Britain Recent papers on the Eagle Owl Bubo bubo (Brit. Wildlife 20: 405–412; Brit. Birds 101: 478–490; see also pp. 213–222) have dis240

cussed the provenance of birds recorded in Britain and the likelihood of the species occurring naturally. I recall that the West © British Birds 103 • April 2010 • 240–242

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Letters Midlands bird on 9th December 1990 was found at the time of the BTO Annual conference at Swanwick, Derbyshire, during which there were blizzards. At the time, Mike Rogers asked me to look at the possibility of this bird being a genuine vagrant. My tentative investigation suggested that it could have been carried from southwest Norway on the northeasterlies of the depression bringing the snow. This opinion was forwarded to MR but the individual was finally presumed to be an escape. The recent papers reminded me of this event and I have taken the opportunity of researching the air-mass trajectories for this period using the latest computer model techniques developed by NOAA, which support my earlier deduction. The depression in question deepened over eastern England during 8th December, subsequently drifting

SSW and filling during the next 24 hours. The northeast winds on its northern flank were strongest during that day and covered the whole of the northern North Sea. The air arriving in the Midlands late on 8th December originated in Rogaland, Norway, less than 16 hours previously. The low-level wind speed added to a notional 35-kph flight speed indicated a ground speed of 100 kph and therefore the duration of the seaward leg of any crossing could have been as little as seven hours. The very strong northeasterly winds, dense cloud and heavy precipitation that covered most of northeast England could conceivably have led to the bird overshooting the east coast by such a margin. Although the owl’s exact provenance will never be known, it may just be the best candidate yet for a genuine vagrant Eagle Owl.

Norman Elkins, 18 Scotstarvit View, Cupar, Fife KY15 5DX

The malar stripe In 1981, an editorial in BB entitled ‘Bird topography’ (Brit. Birds 74: 239–242) set out to standardise the somewhat inconsistent approach to bird topography that had existed in bird books and field guides up to that point. Special mention was made of the differing names given to the various stripes on the lower part of the head of some passerines, such as pipits Anthus and buntings Emberiza. The editorial recommended that they should be named, from top to bottom: (1) the ‘moustachial stripe’, (2) the ‘submoustachial stripe’ and (3) the ‘malar stripe’. This terminology has since been adopted by all authoritative books and journals, such as Svensson (1992) and Svensson et al. (1999), as well as BWP. It remained in use until, in a paper entitled ‘What is the malar?’, Sibley (2001) suggested some amendments to these terms. In particular, he correctly pointed out that the malar stripe is not actually on the group of feathers known as the ‘malar’. This lower stripe in fact runs down the outer edge of the throat feathers and, as a consequence, Sibley recommended that it be renamed the ‘lateral throat-stripe’, a term that has, incidentally, long been used in Sweden. Another advantage of this change was that, in Britain, there has often been a certain amount of British Birds 103 • April 2010 • 240–242

confusion over the term ‘malar stripe’. Sibley also pointed out that what we call the ‘submoustachial stripe’ is actually on the group of feathers known as the ‘malar’. He suggested, therefore, that the term ‘submoustachial stripe’ be abandoned and that the pale stripe that is often present in this area should be simply renamed the ‘malar’, reflecting the group of feathers that it largely follows. Such a move would have the added benefit of bringing Europeans into line with North Americans, who have historically referred to this pale stripe as the ‘malar’. Since there seemed to be no opposition to Sibley’s 2001 recommendations, Vinicombe (2007) followed this new terminology in an article on topography in Birdwatch. Subsequently, LS contacted KEV to question the wisdom of replacing the term ‘submoustachial stripe’ with the ‘malar’. He was concerned about two problems in particular. Firstly, on the skull of an animal the malar actually relates to the upper cheek bone, whereas the feather group in question is closer to the bone of the lower mandible. More importantly, if the former ‘malar stripe’ is changed to the ‘lateral throat-stripe’ and the former ‘submoustachial stripe’ is in turn renamed the ‘malar’, this would introduce an 241

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Markus Varesvuo

Letters years. As a consequence, he did not feel able to moustachial recommend the introduction of ‘submoustachial stripe’ in North submoustachial America, where that particular term has never lateral throat-stripe been widely used. The simplest option would be to accept that the North American and European terminologies are different. There 123. The moustachial and submoustachial stripes and lateral throat-stripe on a is nothing to Rustic Bunting Emberiza rustica (Finland, June 2005). prevent the Eurounnecessary complication that provides peans from continuing to refer to the pale another significant source of confusion. middle stripe as the ‘submoustachial stripe’, a Given that the use of the term ‘malar’ has term that describes the feature both accualways been confusing, LS considered it likely rately and clearly. Although transatlantic unithat it would become even more so if it was formity would be desirable, there are already transferred to a different plumage feature. He other differences in plumage terminologies, could see no objection to the retention of the examples being the ‘supercilium’, which the term ‘submoustachial stripe’, particularly North Americans call the ‘eyebrow’, and the since (1) it describes the mark perfectly and ‘ear-coverts’, which they call either the ‘cheek’ (2) its retention would then necessitate only or the ‘auriculars’. Furthermore, the Amerione change instead of two (i.e. simply cans often refer to the wing-bend area as the changing the traditional ‘malar stripe’ to the ‘shoulder’. It would be similarly unwise and ‘lateral throat-stripe’). difficult to propose the introduction of any This thought had also occurred to KEV, so of these American terms in Europe. we approached David Sibley for his views on For the sake of simplicity, therefore, we the subject. In his response, he stressed the recommend that in Europe the term ‘subpoint that plumage features do not always moustachial stripe’ is retained for the pale relate precisely to the feather groups that stripe between the ‘moustachial stripe’ above underlie them. In many ways, this warrants it and the newly named ‘lateral throat-stripe’ two sets of terminology: one to precisely below it (see plate 123). In North America describe the feather groups themselves and the ‘malar’ will continue to be used for this another, less precise terminology to enable mark. birders to describe plumage markings. References Sibley agreed, however, that the use of the Sibley, D. 2001.‘What is the malar?’ Brit. Birds 94: 80–84. term ‘malar’ has been and remains confusing Svensson, L. 1992. Identification Guide to European and inappropriate – particularly in Europe – Passerines. 4th edn. Privately published, Stockholm. and he considers that there is an argument —, Grant, P. J., Mullarney, K., & Zetterström, D. 1999. Collins Bird Guide. HarperCollins, London. for ‘retiring’ it completely. The problem, Vinicombe, K. 2007.‘Topographical tips’. Birdwatch 176: though, is that the ‘malar’ has been tradition28–31. ally used in North America for at least 100 Lars Svensson, S:ta Toras väg 28, S-260 93 Torekov, Sweden Keith E. Vinicombe, Bristol 242

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Notes Red Kites playing catch? On 17th December 2008, at Calvert landfill, Buckinghamshire, I watched two Red Kites Milvus milvus in the air, seemingly playing a game of catch. The higher bird threw a small object upwards and sideways a distance of about 3 m by spinning around in the air rather like a discus thrower. As the object fell, the lower bird caught it in a talon. The birds

then tumbled about for a few seconds before the bird with the object threw it back to the other bird using the same technique. They flew off into the distance, tumbling, but I didn’t see them making any more throws. This was not the usual food-passing of raptors, which is, I believe, more of a simple drop.

David Ferguson, 21 Amersham Road, Beaconsfield, Buckinghamshire HP9 2HA

Apparent nesting association of Northern Goshawks and Firecrests In 2007, I made several visits to a locality in the Derwent Valley, Derbyshire, to monitor the breeding attempts of a pair of Northern Goshawks Accipiter gentilis. Between May and July, three singing male Firecrests Regulus ignicapilla were also observed at this locality, all within 20 m of the Goshawk nest. Unfortunately, the young Goshawks disappeared when they were about seven days old, but I continued to visit the area to follow the fortunes of the Firecrests. No young were seen but a first-year male and female Firecrest were ringed there in September. In 2008, the breeding Goshawks nested about 1 km from the 2007 site. Their breeding cycle progressed well, aided by a raptor nestwatch scheme. Many unsuccessful attempts were made to find Firecrests at the previous year’s site, but four singing males were recorded within 30 m of the new Goshawk nest during May, June and July. The two localities had similar habitat structure, predominantly European Larch Larix decidua and Sitka Spruce Picea sitchensis, as did much of the general area, and there were no obvious differences, either in habitat or woodland management, between the sites. Four Goshawk chicks were ringed by the Sorby Breck Ringing Group (SBRG) on 23rd May but on 29th May, after heavy rain and gales, the nest and four young were found on the ground. Emergency action was taken by Jack Street (SBRG) and Dave Jones (Forest Enterprise) to erect an artificial nest platform, on which the three surviving young © British Birds 103 • April 2010 • 243–247

were placed, two of which eventually fledged. Proof of breeding by one pair of Firecrests was obtained on 15th July, when they were seen feeding recently fledged young less than 10 m from the recently vacated Goshawk nest. CCTV footage of the Goshawk nest during this period showed that around 95% of the prey items were Grey Squirrels Sciurus carolinensis; other prey included Eurasian Sparrowhawk Accipiter nisus, Eurasian Jay Garrulus glandarius and Great Spotted Woodpecker Dendrocopos major. All of these are potential predators of Firecrests and it seemed plausible that the Firecrests had selectively chosen their breeding site to be close to the Goshawks, especially since searches of apparently suitable habitat elsewhere in the area failed to find any Firecrests. In 2009, only a single male Goshawk was present at the 2008 site, with none at the 2007 site. Three singing male Firecrests were found in May, June and July, but, without a Goshawk nest as a focus, were more difficult to locate along the small woodland valley. Their response to playback tapes of their song was shorter and much more intermittent than in 2008. Symbiotic relationships between raptors and other species have certainly been recorded before and perhaps the best-known example is that of Peregrine Falcons Falco peregrinus and Red-breasted Geese Branta ruficollis in Arctic Russia. In addition, Blanco & Tella (1992) reported a protective 243

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Notes association and breeding advantages of Redbilled Choughs Pyrrhocorax pyrrhocorax in Lesser Kestrel Falco naumanni colonies, while Duncan & Bednekoff (2008) found that cupnesting species were more abundant near to nests of Cooper’s Hawks Accipiter cooperii because of the defence behaviours of the hawks.

Acknowledgments I would like to thank Richard Dale, Hannah Dugdale, Roy Frost and Jack Street for their help with fieldwork and Forest Enterprise and the Severn Trent Water Authority for granting access to their land. References Blanco, G., & Tella, J. L. 1992. Protective association of Choughs nesting in Lesser Kestrel colonies. Animal Behaviour 54: 335–342. Duncan,W. J., & Bednekoff, P. A. 2008. Nesting with the enemy. Ethology, Ecology and Evolution 20: 51–59.

Dr Geoff Mawson, Moonpenny Farm, Farwater Lane, Dronfield, Sheffield S18 1RA

Common Kestrel attempting to predate Hobby chicks at the nest In July 2009, my wife and I watched a Common Kestrel Falco tinnunculus twice attempt to take young from the nest of a Hobby F. subbuteo in Willingham by Stow, Lincolnshire. The nest was an old Carrion Crows’ Corvus corone nest, c. 10 m from the ground in an Ash Fraxinus excelsior tree, in the middle of open farmland. I had watched the nest daily since 14th June and in that time seen both Hobbies (but usually the female) aggressively mob any potential predator that came too close to the nest, including Grey Heron Ardea cinerea, Common Buzzard Buteo buteo, Lesser Black-backed Gull Larus fuscus and Carrion Crow. At 19.35 hrs on 30th July, a female Kestrel landed in a barley field about 15 m from the nest and was immediately mobbed by the female Hobby. Instead of being forced away from the area, however, the Kestrel flew towards and landed at the top of the nest tree, c. 3 m above the nest. The Hobby dived at the Kestrel repeatedly, calling constantly, but the Kestrel seemed unperturbed. When the Kestrel took off, it hovered very briefly then suddenly flew fast and direct straight at

the nest. The Hobby chased it and managed to come between the Kestrel and the nest at the last moment; the Kestrel was close enough to stretch out a talon toward the three chicks (by that time aged 16–18 days) before aborting the attempt. Some five minutes later, the Kestrel reappeared and again landed at the top of the tree just above the nest; the adult Hobby sat tight on the edge of the nest, peering up at the Kestrel. The Kestrel eased its way down through the canopy, edging along branches towards the nest, whereupon the Hobby flew at it aggressively, connecting this time, and forcing it out of the tree. When the two birds emerged they locked talons and both birds dropped down behind a hedge out of sight. The Kestrel presumably flew off low across the field, since the Hobby returned and perched near the nest a few minutes later, when the chicks became visible once more. A pair of Kestrels nested in the adjacent field but I assumed that the aggressive Kestrel was not one of this pair, which I have seen in close proximity to the Hobby nest several times without provoking a response.

Dean Nicholson, 8 Park Road, Willingham by Stow, Gainsborough, Lincolnshire DN21 5LF

Common Ravens and Grey Herons I read with interest the note by Prytherch et al. (Brit. Birds 102: 638) on the relationship between nesting Common Ravens Corvus corax and Grey Herons Ardea cinerea at Chew Valley Lake, Avon. I have been counting up to ten heronries in Ceredigion each year for over 40 years, in a county which has had a ‘saturation-level’ population of Ravens 244

(mostly tree-nesters) throughout that time. The mean spacing of Raven nests in farmland districts, where the heronries are, is about 2 km apart. It appears from casual observation that Ravens are considerably more likely to nest close to heronries, say within 500 m, than would happen purely by chance. In fact, most heronries have nesting Ravens much British Birds 103 • April 2010 • 243–247

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Notes nearer than that, and they have quite frequently bred within a heronry or at its periphery. I doubt that this is due to a shortage of suitable trees, or that Ravens gain some advantage of concealment from the presence of the herons. Ravens are top dogs and have few natural predators here. The advantage is more probably the improved prospect of a good meal, whether eggs, chicks (alive or dead) or surplus food supplied by the herons. Ravens are undoubtedly bad news for herons. One of my heronries, in a mixed conifer plantation at Llanfair, near Llandysul, was I suspect abandoned because of the attentions of Ravens, which, like the Chew Valley pair, were actually using an old heron nest. This heronry, which had existed since about 1925, and had up to 28 nests as recently as 1988, gradually dwindled to just

two pairs by 2004. The birds failed at the egg stage for three seasons before deserting the site in 2006; they have so far not returned. Ravens nested within 100 m since at least 1967, and actually moved into the heronry in the late 1990s. At this and other heronries there has been direct evidence of Raven predation in the form of heron eggshells or the remains of young herons below the Raven nests, and at one site (Llanllyr, Talsarn) in 2009 the farm manager reported twice seeing a Raven taking a young heron from a nest to feed its own young, barely 50 m away. I have, incidentally, had one pair of Red Kites Milvus milvus using an old heron nest within an active heronry, actually in the same large Beech Fagus sylvaticus as three occupied heron nests. The kites failed at a fairly early stage.

Peter Davis, Felindre, Aberarth, Aberaeron SA46 0LP

Spotted Flycatcher nest reconstructed for second clutch In June 2009, a pair of Spotted Flycatchers Muscicapa striata reared four young in a typical nest in a wall recess at West Bagborough, Somerset; the young fledged on 27th June. On 2nd July I saw an adult Spotted Flycatcher, probably the female, removing nest material, either flying off with the fragments or dropping them nearby. The nest was reduced to approximately 20% of its original size, with the lining removed entirely. On 3rd July, new materials were brought in, and the rebuilt nest was completed on 4th, with a new but scanty lining. The first egg was laid

on the morning of 5th July and by 8th four eggs were being incubated. Second clutches are not uncommon in the Spotted Flycatcher, and Campbell & Ferguson-Lees (1972) stated that the same nest may be used twice in one season, but I believe that rebuilding a nest to such an extent is unusual. Reference Campbell, B., & Ferguson-Lees, J. 1972. A Field Guide to Birds’ Nests. Constable, London.

Dr A. P. Radford, Crossways Cottage, West Bagborough, Taunton, Somerset TA4 3EG

Monitoring Hawfinches – another option The Hawfinch Coccothraustes coccothraustes has recently been added to the Red list of Birds of Conservation Concern in the UK (Eaton et al. 2009) and also to the list of species monitored by the Rare Breeding Birds Panel (RBBP). Holling et al. (2009) highlighted how ‘scarce this species actually is in the breeding season’, and the numbers presented must surely represent only a tiny proportion of those breeding. The population decline that triggered its admission to the British Birds 103 • April 2010 • 243–247

Red list was apparent from RSPB woodland surveys between 1984/85 and 2003/04 (Eaton et al. 2009). However, it is one of the more difficult of British birds to monitor effectively, owing to its secretive nature and easily overlooked song, and the timing of any survey work can have a marked effect on the numbers detected. Hawfinches may breed in loose ‘colonies’ (in part of a larger woodland), and I have known two such colonies locally that persisted for several years before 245

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Notes Table 1. Capture and population estimate data for Hawfinches Coccothraustes coccothraustes in the Forest of Dean, Gloucestershire, 2007–09. Site A B C C B B B B

Date spring 2007 spring 2007 1st May 2008 spring 2008 2nd May 2008 spring 2008 26th April 2009 spring 2009

MG 10 6 14 14 5 6 7 10

TC 34 14 39 63 14 17 27 65

M/R 305* 34 133 239* 56 58 350* 102

112 33 63

* Few recaptures (relative to the number of new birds), and these estimates likely to be less reliable. Notes MG: maximum group size seen during a ringing session or during the spring (in each case ‘spring’ runs from late March to the first few days of May) TC: number of individuals caught during a session M/R: mark/recapture estimate for a session and for the spring using the ‘du Feu method’ (see du Feu et al. 1983). Note that the du Feu method was derived in order to help ringers estimate how many birds are in a local population based on a single ringing session, using the number of new birds and recaptures during that session. In this case, it has been used for a single session but also across sessions during a ‘spring’ (as defined above), when the greater number of recaptures gives a more reliable population estimate. AC: the sum of all the different groups visiting during a session. This assumes that all individuals are different, which is likely to lead to an overestimate. Nonetheless, there is some correlation between M/R and AC (where M/R is based on sufficient recaptures) and these are likely to give a much better indication of the total number of birds in the area than MG.

being deserted as breeding sites following woodland management (thinning). Such abrupt abandonment of apparently still suitable habitat can cause additional problems in monitoring. My aim in this note is to incentivise others to establish feeding sites that might help to clarify the local status of the Hawfinch. During recent years I have caught and ringed over 200 in the Forest of Dean, Gloucestershire, at three feeding sites (see Lewis 2007 and Lewis & Clevely 2009 for more detail). This represents a significant proportion of the grand total ringed in the UK: 1,641 to 2008. The sites are baited with black sunflower seeds scattered among the leaf litter. The period when birds visit in late winter is fairly limited; numbers peak in the second half of April, before tailing off abruptly in early May. At this time, the birds are clearly paired and females are developing brood patches; they are presumably attracted to feeding sites when natural food is short and the females are building reserves for egglaying, and the tail-off in numbers doubtless represents a departure for local breeding sites. The feeding sites are c. 8–10 km apart 246

and the limited evidence of movement between sites suggests that most are attracted to the site from a fairly local area (a few kilometres), and that few birds move more than 5 km. The numbers caught at different sites show just how many are present in the local area, and data from ringing sites may be a useful extra means of estimating the local breeding population. Birds generally arrive as part of a small group, and groups continue to visit throughout the day. Recaptures of ringed birds suggest that each group comprises mainly different individuals. Table 1 confirms that the numbers caught on a daily basis far exceed the maximum group size seen. In the absence of a mark/recapture estimate, accumulated daily counts can provide reasonably realistic estimates of the number of birds in the area, and perhaps a more realistic one than either casual recording or specific surveys provide. References du Feu, C., Hounsome, M., & Spence, I. 1983. A singlesession mark/recapture method of population estimation. Ringing & Migration 4: 211–226. Eaton, M. A., Brown, A. F., Noble, D. G., Musgrove, A. J., British Birds 103 • April 2010 • 243–247

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Notes Hearn, R. D., Aebischer, N. J., Gibbons, D.W., Evans, A., & Gregory, R. D. 2009. Birds of Conservation Concern 3. Brit. Birds 102: 296–341. Holling, M., & the Rare Breeding Birds Panel. 2009. Rare breeding birds in the United Kingdom in 2006.

Brit. Birds 102: 158–202. Lewis, J., 2007.Why not try catching Hawfinch for a change? Ringers’ Bulletin 12: 15. — & Clevely, R. 2009. Catching Hawfinch – easier than you might think! Ringers’ Bulletin 12: 82.

J. M. S. Lewis, Y Bwthyn Gwyn, Coldbrook, Abergavenny, Gwent NP7 9TD; e-mail jerrylewis@monmouthshire.gov.uk

Mark Watson

In May 2009, in eastern Poland, we discovered and examined two Hawfinch Coccothraustes coccothraustes nests. One, containing two young aged around 8–10 days, was in a European Larch Larix decidua, close to a lake used by anglers. It was soon apparent that the young were tied together with discarded fishing line, a considerable quantity of which had been used for the nest lining. Presumably, the young had been entangled in the line at an early age and the line had tightened as they grew, constricting the thigh muscles. We cut the young free with scissors (plate 124) and removed all the line from the nest before replacing the young, which hopefully survived. The second nest, in a different area, was notable for the quantity of bright blue baler twine used in the construction and lining (plate 125). This emphasised just how often (potentially dangerous) man-made materials are used as nest liners, and we did contemplate whether the colour had affected the predation risk.

Mark Watson

Hazards of man-made material to nesting Hawfinches

124 & 125. Young Hawfinches Coccothraustes coccothraustes bound together with discarded fishing line (124), and Hawfinch nest with baler twine (125); Poland, May 2009.

N. J. Westwood and M. Watson, 43 Houghton Road, St Ives, Huntingdon PE27 6RQ

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Reviews Collins Bird Guide 2nd edition By Lars Svensson, Killian Mullarney and Dan Zetterström Collins, 2009 448pp, over 3,500 colour illustrations, maps Pbk, ISBN 978-0-00-726814-6 Subbuteo code M17550 £17.99 BB Bookshop price £15.99 Hbk, ISBN 978-0-00-726726-2 Subbuteo code M16237 £25.00 BB Bookshop price £22.00 No fewer than 700,000 copies of the first edition were sold, almost a third of them in the UK, and the Collins Guide has been indisputably the European field guide to birds for a decade now. Does this revised edition give it the wherewithal to maintain that position? Superficially, the new guide is very similar to the old one. The dimensions are unchanged but the number of pages has increased by 12%. The main accounts contain 41 new species (33 of which are the result of taxonomic splits, and most of these receive significantly fuller treatment); many subspecies receive new or more extensive coverage; there are 14 new (double-page) spreads (perhaps most notably Larry McQueen’s unloved American passerines have gone); and in total some 60 plates have been redesigned or repainted. All the maps have been revised, and the texts revisited and improved where appropriate. In the appendices, both vagrants and introduced species benefit from one extra spread. The taxonomy now gives us wildfowl and gamebirds at the beginning, although not the allnew passerine order that the BOU embraced at the start of 2010 (though it is hinted that this is likely to follow in a future edition). On the whole, after comparing the old and the new page by page, and pondering the logistical challenges of updating an existing layout rather than dismantling and starting from scratch, I felt that the improvement was significant. Most, if not all, of the splits and subspecies that were beginning to look like glaring omissions from the old one are covered. Taking the warblers as a case study, we now have full treatment of Eastern Sylvia crassirostris and Western Orphean S. hortensis, Asian S. nana and African Desert S. deserti, Booted Hippolais caligata and Sykes’s H. rama, Eastern H. pallida and Western Olivaceous H. opaca, Eastern Phylloscopus orientalis and Western Bonelli’s Warblers

P. bonelli, plus an entire spread devoted to chiffchaffs of one sort or another and redrawn plates of Radde’s P. schwarzi and Dusky Warblers P. fuscatus. The fact that there is (for example) no Moltoni’s (Subalpine) Warbler S. cantillans moltonii while Eastern Crowned Warbler P. coronatus is still listed in an appendix and (still) without an illustration means that it is not yet the last word on either subspecies or vagrants – but you have to stop somewhere. The names in the first edition were a little quirky, and they still are. For example, although Stercorarius parasiticus is now Arctic (not Parasitic) Skua, and Calcarius lapponicus has reverted to Lapland Bunting, the divers Gavia are still loons and the wheatears Oenanthe will give you a headache. Although the call transcriptions are generally excellent, the Swedish influence on some (the flight call of Redwing Turdus iliacus remains ‘stüüüf ’) is not so helpful for non-Scandinavians. As Killian Mullarney has pointed out elsewhere (Birdwatch 213: 30–32), perhaps the great travesty of this update was that, just four months before the publisher’s deadline, the number of new pages available suddenly jumped from 24 to 48; at that late stage, much of that precious allocation ended up being used to expand the index, an inexplicable lack of foresight that reflects badly on the publisher. Bearing in mind the guidelines that the author and the artists were working with until this late stage, I think one has to conclude that the improvements in the new version are impressive. Is it still the number-one field guide to the birds of the region? Unquestionably, yes. Is it worth upgrading your old one? Yes, on the whole I think it is, and here at least the publisher should be complemented in releasing the paperback version almost as soon as the hardback (which surely few people will buy). The more user-friendly paperback is well worth the relatively modest investment. Roger Riddington

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Helm Dictionary of Scientific Bird Names By James A. Jobling Christopher Helm, 2010 Hbk, 400pp ISBN 978-1-4081-2501-4 Subbuteo code M02538 £40.00 BB Bookshop price £35.00 The first version of this book was published by OUP in 1991, and this is the turbocharged V8 model: bigger, heavier and more powerful. The only thing missing from the first book is the artwork decorating the vacant spaces at the end of each ‘chapter’. Since then, a lot of water has flowed under many taxonomic bridges, with the fragmentation of large genera into smaller units and the promotion of several hundred subspecies to species, providing much new material for the author. There are now over 20,000 entries compared with 8,500 in the 1991 version. Following a page of acknowledgments, a glossary and a list of abbreviations, a ten-page ‘Introduction’ includes the rationale for the new book, a brief history of the binomial system and a short summary of the main rules of the ICZN, and an analysis of the main types of bird names. Then follows seven pages of ‘How to use the dictionary’, which explains the conventions used. The author admits to a limited treatment of eponyms, giving just the basic who, when and occupation, and readers are directed elsewhere for more complete biographies. The meat of the book consists of 483 doublecolumn pages (a 48% increase) of dictionary-like entries with generic names (initial capital) and specific names in alphabetical order explaining the derivation and meaning, with around 25–60 entries per page. The new publisher has made more efficient use of space with a smaller, but still readable, font and closer line spacing. Many entries have been expanded by the addition of who used it, the bird or group to which it applies and

the addition of synonyms. The entry for some more frequently used words has been expanded from a few lines to almost a column. The expanded bibliography now runs to 18 pages. There cannot be that many with sources as diverse as the works of Aristotle, Pliny and a MalayEnglish dictionary! In the Introduction to the earlier book, but not the present one, the author mentioned that the abolition of diacritical marks by the ICZN deprived people of a possible clue to pronunciation; the same wording now appears under the entry for aedon, but has a much wider application. The adjacent initial vowels in this word, and some others with a similar spelling, should be pronounced separately: ay-eedon. As few people are now encountering classics in their education, a more general guide to pronunciation would have been helpful. I have heard cisticola pronounced as sis-TIK-ole˘ and sisti-Kœ-le˘. As the book tells us, the word is derived from Greek kistos, a shrub, and Latin colere, to dwell, so perhaps the initial ‘c’ should be hard. As an aid to use, each page is thumbnailed with the appropriate letter. It would take a classical scholar of considerable expertise to take issue with the author, far beyond my distant struggles with Caesar’s Gallic Wars and Xenophon’s Anabasis. If you ever wondered what those strange words meant and where they came from, this book tells you. You learn quite a lot about Greek and Latin myths too. Reference Jobling, J. A. 1991. A Dictionary of Scientific Bird Names. OUP, Oxford.

F. M. Gauntlett

The Status of Birds in Nottinghamshire By Jason Reece Hoopoe Press, 2009. Pbk, 156pp, line-drawings ISBN 978-0-9560592-0-8 Subbuteo code M20573 £9.50 BB Bookshop price £9.00 Despite its landlocked position, Nottinghamshire has been responsible for some major birds in recent years, including Britain’s first Redhead

Aythya americana, at Bleasby in March 1996, and the Nottingham Cedar Waxwing Bombycilla cedrorum, which arrived the previous month. The

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Reviews county has an impressive list of 325 species and no fewer than four firsts for Britain, so The Status of Birds in Nottinghamshire has the potential for some interesting reading. The first assessment of the county’s birds was Notes on the Birds of Nottinghamshire, by Joseph Whitaker in 1907, and the most recent was The Birds of Nottinghamshire: past and present, by Austin Dobbs in 1975. Though all historical records are noted, the scope of the present book is focused on the period 1975–2007, coinciding with the political boundary changes of 1974 and the last review of the county’s birds in 1975. A brief description of the county is organised by topography, geology and land use. The main body of the book embraces details of all species

recorded in Nottinghamshire, with first and last dates for migrants, significant site counts, records of all rare vagrants and a list of key sites with grid references. The species accounts are pleasantly interspersed with the excellent line-drawings of local artist Chris Orgill. The book is thread bound and approximately 50% cheaper than it would have been in hardback, which should enhance both its durability and appeal. As an instant guide to the breeding and rarity status of all the county’s birds, and with all profits from sales being donated to Nottinghamshire Birdwatchers, I can recommend this book to anyone interested in the region’s birds. Ian Cowgill

Up River: the song of the Esk By Darren Woodhead Birlinn, 2009 Hbk, 160pp, colour illustrations throughout ISBN 978-1-84158-8346 Subbuteo code M20570 £29.99 BB Bookshop price £27.00

Wild Skeins and Winter Skies: paintings and observations of Pink-footed Geese By James McCallum Silver Brant, 2009 Hbk, 100pp, colour illustrations throughout ISBN 978-0-9541695-4-1 Subbuteo code M20556 £35.00 BB Bookshop price £31.50 D a r r e n Wo o d h e a d and James McCal lum are foremost among the most skilled exponents of sketching wildlife in the field. Their work is inspired by first-hand observations and executed in the field with uncanny accuracy and painterly freedom crafted by many years of sitting tucked away in the nooks and crannies of our country’s wildest habitats. All-weather conditions are endured in this pursuit – I can only pray that they have invested wisely in haemorrhoidcream futures! Up River and Wild Skeins and Winter Skies are the latest publications to showcase these talents, revealing the respective artists’ latest ventures into the wilds of Britain, and it is a particular delight to review these books side by side.

Darren Woodhead’s Up River is based on three years as artist in residence around Carlops and the valley of the North Esk River. The subject matter varies from bleak snowscapes, where you can feel the cold blasting from the page, to intimate studies of nesting Common Buzzards Buteo buteo and pages of fungi, which have a cosy Victorian feel to them. My favourites include the series of watercolours of Bullfinches Pyrrhula pyrrhula and a massive composition of Northern Lapwings Vanellus vanellus and Dunlins Calidris alpina. I was lucky enough to see this in the flesh at the Birdfair; it is stunning. Which leads me to my only tiny criticism, the originals are so big that sometimes, even in a good-sized book such as this, the reduction of the image is such that the detail can become a little noisy – maybe too much of a good thing squeezed into a small space. By way of a contrast, James McCallum has chosen one species as his subject. For many years

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Reviews he has painted, drawn or simply watched with care the Pink-footed Geese Anser brachyrhynchus of his native Norfolk. Wild Skeins and Winter Skies is the culmination of this work. It is a brave man who produces a book of paintings based purely on one species, but I think he is canny and knows his local market extremely well and, of course, it is carried with the usual McCallum flair. The pages radiate with light and life, the geese gaggle in their efforts to get off the pages! The hours put into this and the dedication to his beloved geese is clear to see, but this is not just a book of pretty sunsets, there is plenty to be gained for both the art lover and the

serious ornithologist. James has always prided himself on his roughy-toughy out-in-all-weathers approach to his art, but I couldn’t help but notice the word ‘van’ cropping up a few times – is he going soft with age? Both books are large format, well produced and lovely to hold – I have a thing about holding books! Both have been written in a way that is almost as evocative as the paintings themselves and are sympathetically designed. Reason to buy – simply to admire these artists at the top of their game. Dan Powell

Wildlife Photography Masterclass: a beginner’s guide to wildlife photography By Chris Gomersall and David Tipling LPS Creative Media, 2009 63 min DVD Subbuteo code M60045 £19.95 (DVD) BB Bookshop price £17.95 This DVD features two of the UK’s best-known wildlife photographers, Chris Gomersall and David Tipling. Both come across well, and the DVD format is useful in allowing us to watch them at work in the field (and in the back garden), and also in the ‘digital darkroom’. The presentation begins by looking at the ‘kit bag’, and sets out clearly the pros and cons of compact cameras, digiscoping (only briefly mentioned) and digital SLRs with their various lens options. A useful review of hides and camouflage gear is also included, along with frequent reminders that the welfare of the subject must always be the main consideration. Equally sensibly, as this presentation is aimed at the beginner, the discussion focuses mainly on the small-tomedium-range lenses rather than the more expensive, heavyweight telephotos, and discusses what can and cannot be achieved with the various options in this range. This emphasis continues with a series of practical sessions, involving some approachable and accessible subjects, including a family of local Red Foxes Vulpes vulpes. Advice on using food and drink to attract wildlife closer to the camera includes the use of hazelnuts to attract squirrels, which some photographers might find counterproductive! Farther afield, a trip to Bempton Cliffs provides some useful guidance on focusing techniques and problems of exposure at this bird-

photography hotspot. The main session on processing images in the ‘digital darkroom’ (workflow) provides a good grounding for the beginner in what can easily become a highly complex and confusing area, given the wide range of different software programs on offer. Clever camera work clearly shows the actions performed on the computer, zooming in and out of the screen menus to reveal more detail. The additional ‘special features’ at the end of the DVD provide some extra pointers, including the intriguingly named ‘Exposure Bootcamp’ – a title which has more macho promise than it actually delivers. In some ways these extras, particularly the additional session on image optimisation using Adobe Lightroom, come across as slightly vague and random, and may hinder rather than help the main presentation. However, they do illustrate the point that every photographer does things slightly differently, and that beginners need to experiment to discover what works best for them. This DVD covers a lot of ground and, thanks to the wealth of skill and experience on offer from the two photographers, provides a clear and wellpresented introduction to wildlife photography, with lots of practical tips and advice. Bill Baston

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Reviews

The Sounds of Raptors and Falcons By Karl-Heinz Dingler, Christian Fackelmann and Andreas Schulze Musikverlag Edition AMPLE, 2009 Two CDs (156 mins) and 36-page booklet in English, French and German ISBN 978-3-938147-17-7. Subbuteo code V10081 £17.95 BB Bookshop price £15.95 These two CDs present 311 recordings of the calls and other sounds of 103 species of birds of prey – including all those regularly occurring in the Western Palearctic. In addition, the selection offered goes beyond that region to incorporate a range of species from each of the continents, although it is not clear what criteria were used to make the choice. There are over 320 raptors in the world, so only a third are represented here – and while the selection offered for Africa covers most of the commoner species, the same cannot be said for the other continents. There are some strange omissions. For example, several of the caracaras are included, but not Red-throated Caracara Daptrius americanus, which is one of the most vocal raptors I know. From Australia the Black Falcon

Falco subniger is featured – but nothing else. At the other extreme, a recording of chicks of the neglectus race of Common Kestrel F. tinnunculus from the Cape Verde Islands is included. Of particular interest are a series of ten recordings of Red-footed Falcons F. vespertinus, representing the entire breeding cycle from the establishment of a territory to calls of nestlings at the nest and on fledging, as well as alarm calls. The recordings are clear and the booklet provides brief details of each recording, although often without any indication of when or where the recording was made. Further details, including a full list of the species included, are available at www.birdsongs.de Keith Betton

Peregrine Falcon Populations: status and perspectives in the 21st century Edited by Janusz Sielicki and Tadeusz Mizera Turul & Pozna´n University of Life Sciences, 2009 Hbk, 800pp, numerous colour photos and figures ISBN 978-83-920969-6-2 Subbuteo code M20455 £75.00 BB Bookshop price £69.95 This attractively produced volume consists of no fewer than 62 short papers, most of which were presented at the Second International Peregrine Conference, held near Pozna´n , Poland, in September 2007. As befits the conference’s title, the papers are drawn from across the globe, though most (roughly 45%) concern central and eastern Europe. Such a bias is not unwelcome, given that this geographical area has not, to my knowledge, been well covered in earlier English language reviews on the Peregrine Falcon Falco peregrinus. The papers are varied and split into six broad categories: population dynamics, food and feeding, interactions with humans, reintroductions, urban populations, and, as a bonus not even hinted at in the book’s title, a concluding section consisting of four interesting papers on the Saker Falcon F. cherrug in central Europe. There are plenty of intriguing facts to be found, and issues to be thought about. For example, despite a ban on the use of certain organochlorine biocides in Germany, levels

of chemical contamination of Peregrine eggs in that country have not fallen as far as expected, probably owing to DDT residues from anti-malaria campaigns in the tropics being redistributed through the atmosphere to colder regions of the globe. Also disturbing is the matter of male hybrid falcons that have escaped from captivity mating with wild female Peregrines (female hybrids are apparently infertile), as has occurred recently in eastern Germany and in England. In this connection, it was also interesting to read that natural hybridisation has taken place between certain species of large falcon where their ranges meet in North America and Eurasia. Several contributions discuss the decline and subsequent recovery of various Peregrine populations, while on a lighter note there is even a paper considering the use of the images of falcons on stamps. Enthusiastic students of large falcons are sure to find this book informative and thought-provoking. Pete Combridge

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News and comment Compiled by Adrian Pitches Opinions expressed in this feature are not necessarily those of British Birds

Global war(farin) declared on rats as UK seeks to save our seabirds Far-flung seabird islands in the South Pacific and the South Atlantic are set to receive an anti-rodent onslaught that could finally safeguard their endangered seabird communities. Both Henderson Island and South Georgia are UK Overseas Territories that are spectacularly remote with internationally important seabird populations. Henderson Island is in the Pitcairn group in the eastern South Pacific, 5,000 km from New Zealand; South Georgia is in the South Atlantic, 1,500 km east of the Falklands. South Georgia is home to 30 million breeding seabirds. The key species are Grey-headed Albatross Thalassarche chrysostoma, Northern Giant Petrel Macronectes halli, White-chinned Petrel Procellaria aequinoctialis, Antarctic Prion Pachyptila desolata, Macaroni Penguins Eudyptes chrysolophus (half the world population) and the endemic South Georgia Shag Phalacrocorax georgianus. But South Georgia is also home to several million Brown Rats Rattus norvegicus, the descendants of those inadvertently introduced by nineteenthcentury whalers and sealers. The rats devour the eggs and chicks of all ground-nesting birds and will be targeted in a comprehensive eradication programme scheduled for February 2011, masterminded from… Dundee. Invasive rodents have been removed successfully from more than 300 islands worldwide but the South Georgia operation involves two helicopters spreading poisoned bait over every square metre of ice-free land on the 170 km-long island, using the precision of GPS navigation. ‘It’s easily the largest rat-eradication effort in the world, at least seven times bigger than anything anyone has tackled before,’ said Tony Martin, Professor of Animal Conservation at the University of Dundee, who is in charge of the multi-million-pound project. ‘My job is to nail every last rat and to make sure we don’t poison too many non-target species. It’s no good if we end up missing the last couple of rats, because they reproduce so quickly and within a few years their numbers will be back up to present levels.’ The only barriers to the rats on South Georgia are the ice tongues of the glaciers which protrude out to sea and isolate some bird colonies. But these glaciers are retreating rapidly, which means that rats are able to find new bird colonies to attack, Prof. Martin said: ‘The glaciers are retreating at a hell of a pace, sometimes visibly changing year on © British Birds 103 • April 2010 • 253–256

year. When the snout of a glacier melts away from a beach, the rats just walk around it. It’s happening very quickly, which is why we need to work fast.’ Pellets of a cereal bait loaded with an anticoagulant poison will be spread across all ratinfested parts of the island by helicopter. The poison, which quickly degrades and does not dissolve in water, works by getting into the liver and causing internal bleeding. It does not kill immediately and makes the rats sensitive to light so it is hoped they will retreat to their burrows to die underground rather than dying out in the open where their poisoned corpses could be eaten by seabirds. Meanwhile, the RSPB is researching the eradication of the Pacific Rat R. exulans on Henderson Island in August–September 2011 or 2012. Henderson is the most pristine raised coral atoll of significant size in the world. Declared a UNESCO World Heritage Site in 1989, the island has four endemic landbirds: the Henderson Fruit Dove Ptilinopus insularis, Henderson Lorikeet Vini stepheni, Henderson Crake Porzana atra and Henderson Island Reed Warbler Acrocephalus taiti. It is also the only known nesting site of the Henderson Petrel Pterodroma atrata and represents the ‘global headquarters’ of the highly threatened gadfly petrel group, with four breeding species. Evidence from fieldwork has shown that Pacific Rats kill 99% of the chicks of the four species of petrel (Henderson Petrel, Herald Petrel P. heraldica, Murphy’s Petrel P. ultima and Kermadec Petrel P. neglecta) that occur on Henderson. Population modelling shows that these petrels are in long-term decline, with their numbers having dropped from the order of millions before rats arrived to just thousands now. The rats are also likely to be reducing populations of turtles and other wildlife on Henderson, and competing for food with the fruit dove, lorikeet and crake. One of the RSPB’s key aims is to convince the UK Government to accept and honour its legal obligation to protect the biodiversity of this unique island, and another is to secure funding for the removal of rats from Henderson Island. If rat eradication (estimated cost: £1.5 m) is successful, it’s believed that seabird populations could be boosted one hundredfold within a relatively short time frame. And a paper about Henderson Island in the series describing key Important Bird Areas (IBAs) will appear in BB later this year. 253

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Raven increase does not spell the end for threatened waders Common Ravens Corvus corax are not responsible for the dramatic declines in the numbers of wading birds seen in many parts of the UK uplands, according to the results of a new study by RSPB and the University of Aberdeen’s Centre for Environmental Sustainability (ACES). The uplands are home to many waders, including European Golden Plovers Pluvialis apricaria, Northern Lapwings Vanellus vanellus, Dunlins Calidris alpina and Eurasian Curlews Numenius arquatus, which have declined by up to 50% in the last quarter century. In contrast, Raven populations have recovered in many parts of the UK during that same period. These patterns, together with the knowledge that Ravens will eat the eggs and chicks of upland waders, have led some to suggest that Ravens are the cause of wader declines, and to demands by some land managers for licences to kill Ravens to protect upland breeding birds.

RSPB data from sites distributed across more than 1,700 km2 of the UK’s uplands were used to explore the patterns of change in Raven numbers and wader abundance over the past 20 years. In the UK, the Breeding Bird Survey shows that from 1994 to 2007 the Raven population increased by 134%. The research found little evidence to suggest that wader populations were more likely to decline where Raven populations had increased, however. This implies that other factors, including changes to habitat and vegetation cover, and a general increase in other predators such as Red Foxes Vulpes vulpes, could be responsible for these largescale changes. The study did find weak associations between increases in Ravens and declines in Lapwings and Curlews, but these were not statistically significant. Further research is needed to explore these patterns and consider the impact of habitat changes on waders.

Waxwings on the move

Walter Burns

Aberdeen is the UK’s capital city of Waxwings Bombycilla garrulus. Its location in relation to Scandinavia means that if there is any widespread movement of Waxwings, some usually turn up in Aberdeen. The abundance and variety of berries in the city attracts and holds birds and in the larger invasions flocks of over 1,000 have been recorded. Grampian Ringing Group has been colourringing Waxwings in and around Aberdeen since 1988. Thanks to many birders, photographers and members of the public providing sightings and

recoveries of dead birds, the results have produced an interesting picture of the birds’ southward movements through Britain & Ireland after landfall in North-east Scotland. Unfortunately, once the Waxwings depart to their remote summer breeding grounds, few are ever heard of again. So, when small numbers started to arrive in February 2010, it was an exciting surprise to have a colour-ringed bird return to the same village where it had been ringed (as an immature female) in February 2009. Plate 126 shows the colourringed Waxwing feeding on apples in the garden of Walter and Ann Burns in Kintore, near Aberdeen. This is only the third confirmed record of a Waxwing returning to the UK in a subsequent winter from over 4,500 birds ringed. In contrast, an adult male ringed in Aberdeen on 31st March 2005, during the very large invasion of winter 2004/05, was killed by a cat the following February… in a Russian village east of the Urals, 3,714 km northeast of its ringing location the previous winter.

126. Adult female Waxwing Bombycilla garrulus, Kintore, North-east Scotland, February 2010, returning to the very same village where it had been ringed a year earlier. 254

(Contributed by Raymond Duncan)

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The Big Mammal Year Many (most?) birders keep a year list, be it for their country, county or just for their garden. Those 2010 British year lists should soon be accumulating their first Barn Swallows Hirundo rustica, Common Whitethroats Sylvia communis and Willow Warblers Phylloscopus trochilus. Some well-heeled and/or well-travelled people also keep a world year list. The record breakers in world birding are Alan Davies and Ruth Miller, whose Biggest Twitch around the world in 2008 yielded a staggering 4,341 species, a quantum leap beyond the previous record of 3,662 seen in a single year (www.thebiggesttwitch.com) Now two South Africans, Rich Lindie and Hayley Wood, have decided to make 2010 a ‘big year’ – for mammal watching. And they’re hoping to raise $100,000 for mammal conservation along the way. There are 5,500+ species of mammal in the world (roughly half the c. 10,000 bird species) and the couple hope to see about 400. Theirs is not an attempted record-breaking tour but an opportunity to see, photograph and raise the profile of the most endangered species. Roughly one-fifth of mammal species fall into this category. To find out more, visit www.thebigmammalyear.com

Seabird conservationist nets $150,000 award to research fisheries Dr Ben Sullivan, a Tasmanian-based co-ordinator for BirdLife’s Global Seabird Programme, has been awarded a 2010 Pew Fellowship in Marine Conservation for his project to reduce seabird ‘bycatch’ (the catching and killing of non-target species) in open ocean longline and trawl fisheries. The Pew Fellowship in Marine Conservation gives recipients $150,000 for a three-year scientific research or conservation project designed to address critical challenges facing our oceans. Dr Sullivan’s fellowship will utilise the existing Albatross Task Force to conduct research and develop best practices for reducing the killing of seabirds in many of the bycatch ‘hotspots’ around the world. ‘I am thankful to the Pew Marine Fellows Program for allowing me to research new and better ways to protect seabirds from unnecessary deaths at the hands of fishing gear,’ said Dr Sullivan. ‘Finding new solutions to the problem of bycatch in fisheries will signify an important step toward stopping the decline of many seabird populations.’

Bumblebees not so vulnerable

Biking birder update

Renowned weather watcher Norman Elkins responded to the recent piece about the Big Freeze and the threat to hibernating bumblebees (Brit. Birds 103: 133). He says: ‘Regarding bee mortality, I fear the comments by the Bumblebee Conservation Trust are rather misleading. Not only have we had air temperatures as low as this winter’s in previous winters (the -20°C being the exception rather than the rule), but such low minimum temperatures usually occur only above extensive snow cover (which radiates very efficiently, leading to severe temperature decreases overnight). However, the snow acts as a blanket, keeping ground temperatures at or just above zero. Thus bees hibernating underground are well protected from the very low temperatures (with -11°C and 20 cm of snow in my garden, I was still able to dig vegetables from the soft unfrozen ground beneath). ‘With such widespread snow across the UK, I suspect that most bees were quite comfortable beneath the snow cover. If this was not the case, there wouldn’t be very many bees left in northern Europe!’

Gary Prescott (see Brit. Birds 103: 135) has had an eventful start to his birding/biking year around Britain, in the coldest British winter for 30 years. Broken lights after a fall on the ice, three days stuck in Hemel Hempstead because of the snow (he finally escaped along the towpath of the canal to Uxbridge, pushing the loaded bike the whole way), and nearly being arrested in London’s St James’s Park for looking and acting like a terrorist (heavy camouflaged fatigues to combat the snow, plus binoculars and notebook) were just some of the challenges he faced. By early March, he had reached Cornwall and 149 species for his year list, including goodies such as Green-winged Teal Anas carolinensis, Lesser Scaup Aythya affinis, Ring-necked Duck A. collaris, Great White Egret Ardea alba and Great Grey Shrike Lanius excubitor. Follow Gary’s journey on www.bikingbirder.co. uk, where his itinerary is listed – if you can offer company or a bed for the night at any point, please get in touch. His mission is to cycle to every RSPB and WWT reserve in the UK, in support of those two charities plus Asthma UK.

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BB Bird Photograph of the Year, sponsored by Warehouse Express A reminder that the 34th BB Bird Photograph of the Year competition is still open for entries. The competition is FREE to enter and up to three images of Western Palearctic birds taken during 2009 may be submitted. The first prize is a cash

prize of £1,000, and the closing date for entries is 24th April. For full details of the rules and how to submit entries, visit www.britishbirds.co.uk/bpy.htm

The World’s Rarest Birds

Owls of the world – a request for photographs

A rather different photographic competition is now online at www.theworldsrarestbirds.com Photos of 623 species, listed on the website, are eligible for the competition and many will be used in The World’s Rarest Birds, which will be published in the first half of 2011. The World’s Rarest Birds has evolved from Rare Birds Yearbook and will be produced by WILDGuides, a not-for-profit publisher and, as with Rare Birds Yearbook, proceeds from sales will be donated to BirdLife International’s Preventing Extinctions Programme. The new format will be expanded to cover the 362 species categorised as Endangered as well as the world’s 192 Critically Endangered species. For more information contact Erik Hirschfeld editor@theworldsrarest.com or Andy Swash andy_swash@wildguides.co.uk

In 2012, A&C Black will publish a definitive photographic guide to the world’s 250 species of owls, and the process of sourcing and selecting photographs is now well underway. Owls of the World is being written by Finnish owl guru Heimo Mikkola, and the publishers would like to invite the submission of images (preferably digital) for use in the book, which will place particular emphasis on plumage variation and racial separation. Photographs of young birds, island endemics and adults in flight are particularly welcome. If you think that you might be able to help, please contact Ellen Parnavelas: eparnavelas@ acblack.com

And finally: Black Woodpecker in Cumbria – still showing well It seemed too good to be true. A much-hoped-for – and frequently claimed – first for Britain had been staked out in Cumbria. Indeed, it seemed to be ‘nailed on’ for anyone wishing to make the journey to the Lake District. The Black Woodpecker Dryocopus martius at Ling Fell near Bassenthwaite Lake was indeed nailed on, however, as soon became apparent. The first report was phoned through to the BirdGuides sightings hotline www.birdguides.com by a local resident, and she was very detailed in her description: ‘I was on the lower slopes of Ling Fell, near Wythop Mill, and the Black Woodpecker was on a telegraph pole. Because I was coming downhill towards him, he was not far above eye-level at first. He stopped pecking and froze, and though I stopped and watched for a good five minutes, he did not move. I’ve checked the books and there’s absolutely no doubt that’s what he was.’

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She was perfectly correct in her identification and the bird is still showing well – it’s a metal model nailed to an electricity pole. It transpired that power company United Utilities use models of Black Woodpeckers to deter Great Spotted Woodpeckers Dendrocopos major from drilling holes in their wooden electricity poles, which cost up to £1,500 each. Polly Rourke from United Utilities told BBC Look North: ‘We’ve been using these models for about five years because (Great Spotted) woodpecker attack is one of the biggest causes of electricity pole damage… They make huge holes in the poles, which can render them unstable. It makes it impossible for our engineers to climb them and there could be a risk of power cuts.’ And no, despite the date on the front cover of BB, this is not an April Fool!

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Recent reports Compiled by Barry Nightingale and Eric Dempsey This summary of unchecked reports covers early February to early March 2010.

Headlines American waterbirds provided most of the highlights, including two Piedbilled Grebes, a Pacific Diver and a Common Eider of the American race dresseri in Ireland, and a Bufflehead in Dorset. A trio of Phylloscopus warblers injected some passerine interest, particularly a Dusky Warbler, the first for the London area. Red-breasted Goose Branta ruficollis Longstayer in Devon to 28th February; Pitsea (Essex), 4th–5th March. American Wigeon Anas americana Longstayers in Co. Cork and Dumfries & Galloway. Baikal Teal Anas formosa Tacumshin Lake (Co. Wexford), long-stayer seen again, 19th–23rd February. Black Duck Anas rubripes Long-stayer in Co. Mayo; also Colliford Lake (Cornwall), 16th February to 6th March. Blue-winged Teal Anas discors Longstayer in Co. Dublin.

Pacific Diver Gavia pacifica Between Doorus Pier (Co. Galway) and Finvarra (Co. Clare), again, 4th–6th March. Cattle Egret Bubulcus ibis Sennen, up to two long-stayers to 3rd March, Tresillian/Tresemple Pool, up to three long-stayers to 19th February, Wadebridge, 19th February, and Hayle Estuary (all Cornwall), 6th March; Great Island (Co. Cork), 4th–28th February; Walmer (Kent), 2nd March; Sharpham Park (Somerset), long-stayer again 3rd–7th March. Great White Egret Ardea alba Records from Cambridgeshire, Carmarthenshire, Cheshire & Wirral, Dorset, East Glamorgan, Greater London, Gwent, Hampshire, Kent, Lancashire & N Merseyside, Northamptonshire, Somerset, Suffolk, Warwickshire, Yorkshire.

Paul Kelly www.irishbirdimages.com

Ferruginous Duck Aythya nyroca Chew Valley Lake (Avon), again, 20th February. Lesser Scaup Aythya affinis Long-stayers in Cornwall and East Glamorgan; also Lewis (Outer Hebrides), two, 10th February; Eglwys Nunydd Reservoir (East Glamorgan), inter-

mittently, 13th February to 5th March; Hogganfield Loch (Clyde), 22nd February to 6th March; Chew Valley Lake, 7th March. Common Eider Somateria mollissima Drake of American race dresseri, Glasagh Bay (Co. Donegal), from early January to 3rd March. King Eider Somateria spectabilis Burghead (Moray & Nairn), long-stayer joined by another from 19th February to 1st March. Bufflehead Bucephala albeola Abbotsbury/ Langton Herring/The Fleet (Dorset), 6th–8th March. Hooded Merganser Lophodytes cucullatus Long-stayer in Cleveland to 1st March.

127. Drake Common Eider Somateria mollissima of American race dresseri (right-hand bird above, in both cases), Glasagh Bay, Co. Donegal, February 2010; potentially the first record for the Western Palearctic. © British Birds 103 • April 2010 • 257–258

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Recent reports Glossy Ibis Plegadis falcinellus Long-stayers from the 2009 influx comprised three in Somerset and one in Co. Wexford. Pied-billed Grebe Podilymbus podiceps Lough Gur (Co. Limerick), 19th February to 6th March; Lough Ateduan (Co Clare), 5th–7th March. Black Kite Milvus migrans Gigrin Farm, Rhayader (Radnorshire), long-stayer to 7th March. Gyr Falcon Falco rusticolus Islay (Argyll), found dead 14th February; Tresco (Scilly), 13th February and 5th March; Maer Lake, 18th February, presumed same near Newquay (both Cornwall), 24th February. American Golden Plover Pluvialis dominica Waxham (Norfolk), 16th February; Cranwell, 1st March, presumed same Brant Boughton (both Lincolnshire), 2nd March. Long-billed Dowitcher Limnodromus scolopaceus Maer Lake, 12th–19th February; Burton Marsh/ Inner Marsh Farm (Cheshire & Wirral), 14th–16th February; Tacumshin Lake, 20th–23rd February; Ashton’s Callows (Co. Tipperary), 5th March; Banks Marsh (Lancashire & N Merseyside), 7th–8th March.

Laughing Gull Larus atricilla Between Bexhill and Cooden (Sussex), 14th–20th February. ‘Thayer’s Gull’ Larus glaucoides thayeri Cleggan (Co. Galway), from 19th January to 10th February. Bonaparte’s Gull Chroicocephalus philadelphia Baltimore (Co. Cork), long-stayer to 5th February; Lligwy Bay (Anglesey), 1st–2nd March; River Taff (East Glamorgan), 7th–8th March. Forster’s Tern Sterna forsteri Long-stayer in Co. Galway to 6th March. Snowy Owl Bubo scandiacus Lewis, 17th February. Penduline Tit Remiz pendulinus Grove Ferry (Kent), long-stayer to 19th February; Rainham Marshes (Greater London/Essex), 15th February. Pallas’s Leaf Warbler Phylloscopus proregulus Braintree (Essex), 1st March. Hume’s Warbler Phylloscopus humei Strumpshaw Fen (Norfolk), 13th February. Dusky Warbler Phylloscopus fuscatus Walthamstow (Greater London), 14th–21st February. Rose-coloured Starling Pastor roseus Kendal (Cumbria), longstayer to 1st March.

Paul & Andrea Kelly www.irishbirdimages.com

Black-throated Thrush Turdus atrogularis Newholm (Yorkshire), longstayer to 28th February.

128. Long-billed Dowitcher Limnodromus scolopaceus,Tacumshin Lake, Co.Wexford, February 2010. 258

European Serin Serinus serinus Rainham Marshes, two long-stayers to 24th February. Little Bunting Emberiza pusilla Dunnet (Highland), longstayer to 7th March; Sconner (Cornwall), 18th February to 7th March; Lundy (Devon), 22nd–24th February.

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