Warbler - British Trust for Ornithology

y KEN ETH WILLlAMSO F.R.S.E. 

(Population Research Officer B.T.O.) 

IDENTlFICATIO GUIDE NUMBER 0 E 

FIELD GUIDE UMBER SEVE"Il 

1 

The Genera 

CETTIA 

LOCUSTELLA 

ACROCEPHALUS 

and 

HIPPOLAIS 

OCTOBER 1976 

Revised Edition

IDENTIFICATION FOR RINGERS 1 

(B.T.O. Field Guide No. 7) 

by K. Williamson, F.R.S.B. 

First Edition August 1960 

Set'ond Edition March 1963 

Third Edition April 1968 

Reprinted June 1974 

Reprinted October 1976 

Reprinted May 1983 

Covn Design by ROBOT GILLMOR 

Frontispiece drawing by D. I. M. WALLACB

Introduction 

Preface to the Second Edition 

Preface to the Third Edition 

Genus CETTIA 

cetti Cetti's Warbler 

CONTENTS 

Page 

Genus LOCUSTELLA 

luscinioides Savi's Warbler 13 

fluviatilis River Warbler 14 

fasciolata Gray's Grasshopper-Warbler 16 

naevia Grasshopper-Warbler 17 

lanceolata Lanceolated Warbler 19 

Pallas's and Middendorff's Grasshopper-Warblers 21 

certhiola Pallas's Grasshopper-Warbler 21 

ochotensis Middendorff's Grasshopper-Warbler 24 

Genus ACROCEPHALUS 

melanopogon Moustached Warbler 25 

schoenobaenus Sedge-Warbler 28 

paludicola Aquatic Warbler .. 30 

bistrigiceps Schrenk's Sedge-Warbler 3I 

sorgophilus Speckled Sedge-Warbler 33 

scirpaceus Reed-Warbler 34 

palustris Marsh-Warbler 37 

dumetorum Blyth's Reed-Warbler 39 

The Paddyfield Warbler 40 

agricola Paddyfield Warbler . . 41 

concinens Swinhoe's Reed-Warbler 42 

The Great Reed Warblers 44 

arundinaceus Great Reed-Warbler 44 

stentoreus Clamorous Reed-Warbler 49 

orinus SI 

aedon Thick-billed Warbler 52 

5 

9 

10 

II

Genus HIPPOLAIS 

Notes on Field identification 

icterina Icterine Warbler 

polyglotta Melodious Warbler 

pallida Olivaceous Warbler 

caligata Booted Warbler 

olivetorum Olive-tree Warbler 

languida Upcher's Warbler 

Tables of measurements 

Keys to genera and species 

Acknowledgements 

References 

Index to scientific names 

PLATES 

I. Savi's Warbler. Eric Hosking. 

II. Gray's Grasshopper-Warbler. Irene Neufeldt. 

III. Grasshopper Warbler. Eric Hosking. 

IV. Moustached Warbler. C. C. Doncaster. 

V. Sedge Warbler. Eric Hosking. 

VI. Great Reed-Warbler. Eric Hosking. 

VII. Thick-billed Warbler. Irene Neufeldt. 

VIII. Icterine Warbler. Eric Hosking. 

53 

55 

57 

58 

61 

63 

64 

.. 66 

•. 70 

75 

1

INTRODUCTION 

THERE IS LITTLE DOUBT that the next decade will see a great change 

in field-ornithology in this country, and the pattern ofthis change 

is already becoming clear. The growing enthusiasm for serious 

field-work, including migration studies along lines established by 

bird observatories-both at permanent observatories and at new 

and often temporary situations pioneered by keen amateurstogether 

with the increasing use ofmist-nets and the development 

of other trapping teclmiques as an aid to bird-ringing, bring the 

rare bird within reach of every active worker, and invest him 

with a greater responsibility for correct identification than ever 

before. 

No fewer than thirty new forms were added to the British 

avifauna between 1947 and 1959, eleven of them of Palearctic 

origin-an average of one new Palearctic bird a year; and, with 

increasing opportunities and efficiency, there is no reason why this 

rate should not be continued. Species and subspecies which have 

occurred on only one or a few occasions will come to notice 

more frequently, and some which have not yet been admitted to 

the British List (and which are not therefore described in The 

Handbook ofBritish Birds or P. A. D. Hollom's more recent work) 

may be expected to appear. We have already reached the stage 

where the genus Hippolais is proving something ofan embarrassment, 

due to incomplete knowledge of the species characters at 

different seasons; and there are other genera such as Acrocephalus, 

Locustella and PhYlloscoPus which are equally fraught with potential 

headaches for the man with a mist-net or a Heligoland trap. 

Since the basis of all knowledge is correct identification-not 

only ofspecies, but ofrace, age and sex where possible-the time 

is ripe for a publication designed to arm the field-worker with 

such information, in a condensed form, as will enable him to 

identify in the hand the rare species and 'extra-limitals' which 

could conceivably come his way in the course of trapping and 

bird-ringing.

6 INTRODUCTION 

Scope ofthe Work 

This is not a formal taxonomic review, and my main purpose 

has been to ferret out points which I think: will assist the identification 

in the hand of those birds, species or subspecies, which 

have even an outside chance ofdrifting to the British Isles. It has 

nevertheless been necessary to adopt a taxonomic approach, since 

at one or two points I have found myself in disagreement with 

the most recent review, Charles Vaurie's The Birds ofthe Palearctic 

Fauna-a Systematic Reference. This excellent work deals most 

competently with relationships and distribution, buthas the drawback 

for the field-taxonomist that it lacks the plumage descriptions, 

wing-formulae and measurements which are fundamental to 

correct identification. It should, however, be in the library of 

every bird observatory, and access to it cannot but enhance the 

competence ofall who trap and ring migrants on any scale. The 

reader is referred to this work for a full statement ofdistribution, 

since only the bare outline is given in the Guide. 

I have kept plumage descriptions to a minimum: in the case of 

the more familiar birds, adequate data are given in The Handbook 

and The Popular Handbook, whilst illustrations can also be found in 

the field-guides ,by Peterson, Mountfort and Hollom, and Fitter 

-and Richardson, to mention a few recent works. For this reason, 

more space is allotted to a discussion of the unfamiliar extralimital 

forms, and those in which confusion with a commoner 

species could arise. In these genera the sexes are alike in plumage; 

in general, rst-winter birds are separable from adults, and the 

main points of distinction are given. The information on the 

colours of bill, legs, inside of mouth and iris has been culled 

partly from the literature, and partly from collectors' notes on the 

labels ofmuseum specimens, written when the birds were freshly 

killed. Since the work is intended for the use ofthose who handle 

birds, I have not added to its bulk by setting down field-characters 

(except in a few special cases) but have included references to notes 

on this subject in the journals. 

Many of these birds have narrow, dark 'fault-barring' across 

the tail; such bars arise during the growth ofthe feathers, resulting 

from their irregular protrusion from the protecting sheaths, and 

their presence is not therefore mentioned under the separate 

species. In some cases, where it may aid identification, the wing! 

tail ratio (or tail-length expressed as a percentage of winglength) 

is given under 'Measurements'. 

d

8 INTRODUCTION 

introduce difficulties and increase the risk of misidentification, it 

has seemed better to keep to the 'traditional' convention for the 

statement of wing-formulae. For the most reliable method of 

measuring a live bird, and noting the wing-formula, see B.T.O. 

Field Guide no. 6, The Bird in the Hand, by R. K. Cornwallis and 

A. E. Smith. 

In the sections dealing briefly with moult, however, the opposite 

system of numbering has 1:Jeen used, not only for the very 

good reason that the moult of primaries is descendant, but also 

because practically all writers on the subject have followed this 

system, and it seems best to fall into line. This duality introduces 

a seeming inconsistency into the present work, but should satisfy 

both those whose main concern is easy and accurate identification, 

and those whose interests lean towards morphological studies. As 

an additional safeguard against the possibility of confusion, a 

reminder as to which system is employed, ascendant ordescendant, 

is given in appropriate places in the text. 

I have set out the wing-formula data in such a way as to facilitate 

comparison ofone form with another, and for ease of reference 

the same scheme has been maintained throughout. In this section 

it will be understood that'+' and '-' are shorthand for 'longer 

than'd'h an sorter th' an , th at " p. and" s. represent,., pnmary and 

'secondary' (with 'pp.' and 'ss.' as the plural), and that 'p.c.' means 

'primary coverts'. The figures (unless otherwise stated) express a 

value in millimetres shorter than the wing-point or tip of the . 

longest primary in the closed wing. In the absence ofa statement 

to the contrary, the wing-formula given is good for all the races 

mentioned under the species. 

The time of the post-nuptial moult of remiges and rectrices is 

often important in enabling the trapper to determine the age of 

his bird. Moult in Palearctic passerines has been surprisingly little 

studied, and this is a field in which those who handle live birds for 

ringing can make a valuable contribution to our knowledge. The 

statements given in The Handbook are unfortunately not always 

reliable and often conflict with one's fmdings after studying 

museum material. Partly for this reason, and partly to emphasize 

the value and importance of this aspect of ornithology, I have 

dealt with moult in some detail, giving an account ofhow and 

when this takes place, in so far as I have been able to determine 

the facts from skins. As the B.T.O. Moult Enquiry (see Corn- 

T 

d

INTRODUCTION 9 

wallis and Smith, 1960) gets under way, our knowledge in this 

field will increase. Meanwhile, it will be clear from the little 

information available for most species that a full statement will 

not be possible for many years to come-indeed, perhaps not 

until trapping and ringing in Africa, India and S.E. Asia tmdergo 

a similar revolution to that which is apparent in Britain today. 

British Trust for Ornithology KENNETH WILLIAMSON 

(Migration Research Officer) 

PREFACE TO THE SECOND EDITION 

IN REVISING Identification for Ringers no. 1 the opportunity has been 

taken to enlarge and re-cast the material so that this new edition 

will be more nearly a companion-volume to guide no. 2, which 

deals with the genus Phylloscopus. 

As in that guide, I have arranged the birds of the 'reed-marsh' 

group ofwarblers in accordance with primary plumage characters 

and size, and this has meant sinking two monotypic genera, 

Lusciniola and Phragamaticola. The genus Acrocephalus is a very 

varied one in so far as wing-formula and structural characters are 

concerned, and I can see no grounds which seem to me to justify 

the separation ofthe Moustached Warbler melanopogon from the 

streaked members ofAcrocephalus in a genus of its own. Indeed, 

this almost traditional arrangement has tended to obscure the 

bird's true relationship, for Dresser (1902), Hartert (1910), The 

Handbook of British Birds (1938) and many other works interpose 

the genus Locustella between the Moustached and the closely 

similar Sedge- and Aquatic Warblers. Colin Harrison and Shane 

Parker, working independently on this group at the British 

Museum (Natural History), hold similar views, and recommend 

that Lusciniola should be synonymized with Acrocephalus (Bull. 

RO.C., in press). 

There might be more justification for upholding the monotypic 

genus Phragamaticola, in view ofthe Thick-billed Warbler's 

exceptionally rounded wing, long rounded tail, and short bill;

14 LOCUSTELLA LUSCINIOIDES 

Cambridgeshire birds, both sexes, measure wing 68-71, tail 

S3-S6 (61). 

Tail markedly rounded, IS-18. Wing/tail ratio of S4 birds, 

76-90. Under tail-coverts extend beyond outermost tail feathers. 

Wing-formula (pp. ascendant). No emargination. 1st p. = p.c. to 

3-p·c. 

Wing-point, 2nd, rarely = 3rd; otherwise 3rd, t-3; 4th, 4-6; 

sth, 6-9; 6th, 9-II; 10th, 17-19. 

2nd without notch. Outer pp. distinctly curved. Longest tertial 

= lOth p. or to 4 shorter. 

Moult (pp. descendant). Adults moult in Africa. In a collection from Darfur, 

Sudan, wing and tail had just started in early October. Birds dated 16.x. and 

23.X. have the wing-moult well advanced and the whole tail growing. A bird 

dated 9.xi. has finished the tail and pp. 1-3 and has pp. 4-10 all growing together 

in both wings. Thus the moult appears to progress with remarkable rapidity 

and must leave some birds flightless for a time. 

Distribution. Local in Europe east to Riv. Volga, from Holland south to the 

Mediterranean and N. Africa. Regular breeding England (E. Anglia) ceased 

about 1856, since when accidental until re-established in N. Kent 1960 or 

earlier, increasing to 12 singing males by 1967: see R. G. Pitt (1967). Has also 

occurred in recent years in Somerset. Wiltshire. Sussex, Suffolk. Norfolk, 

Lincolnshire. Once Scotland (Fair Isle), 14.V.lgo8. Once Sweden, I2.vi.1947. 

Denmark, one in May 1949. 8 in four localities 26.v.-15.vii.1964, and one 

in May 1965 (Niels Otto Precess. D.O.F. T. 61 :164-7). 

L. luscinioides fusca Severtzov. 

The race fusca from Turkestan is decidedly olive-brown. not 

rufous, above, and whiter beneath, with the brown offlanks and 

under tail-coverts paler. Measurements and wing-formula are as 

in the typical race. 

Weight. Oxford Univ. Exped. N. Iran, August 1963, average of 

14 birds, IS.3 (II,6-I8.4) gm. 

Distribution. W. Siberia across Kirghiz Steppes south to Transcaspia and the 

Tian Shan range. 

LOCUSTELLA FLUVIATILIS (Wolf) 

River Warbler 

Uniform olive-brown mantle contrasting with warm brown 

tail. Dark brown mottling on white throat and duller breast, 

centre of belly whitish, sides of breast and flanks olive-brown. 

Under tail-coverts buffish-brown broadly tipped white. Under- 

t

7 

LOCUSTELLA FASCIOLATA 17 

Tail markedly rounded, 22-25. Wing/tail ratio of 29 birds, 

83-94 (c£ fiuviatilis). 

Wing-formula (pp. ascendant). Emarginated 3rd. 1st p. minute, 

about half p.c. 

Wing-point, 3rd. 4th, 2-3i; 5th, 6-8; 6th, 8-12; loth, 17-19. 

2nd usually falls between 3rd-4th. Notch on inner web 9-12 

from tip, falls between 6th-8th. 

Moult (pp. descendant). A November bird from the Moluccas is very worn. 

Migrants in mid-May and June birds from the breeding grounds are comparatively 

fresh, so that the complete moult probably takes place late in the winter. 

Distribution. Central and E. Siberia north to 60° N. on Tunguska Riv., east 

across Transbaikalia to Amurland, Ussuriland, N. Manchuria, Sakhalin, Kurile 

Is, Hokkaido, Korea. Migrates through E. China and R yukyu Is to Philippines, 

New Guinea, Celebes and other islands of S.E. Asia. Vagrant to N.W. France 

(see above). 

LOCUSTELLA NAEVIA (Boddaert) 

Grasshopper- Warbler 

L. naevia naevia (Boddaert) 

Upper parts warm olive-brown with broad blackish streaks. 

No supercilium. Dimorphic, under parts whitish in some, yellowish 

in others, irrespective of age or sex. Sides of breast washed 

buff; often a row ofbrown spots across lower throat. Flanks and 

under tail-coverts pale brown, the latter with dark brown shaftstreaks. 

Outer web of long outermost p. brownish-white. 

Haunts dry as well as marshy localities-heaths, dunes, young 

conifer plantations-where there is sufficient scrub or growth of 

bushes. Occasionally in crops; also on chalk-grassland and heathermoors. 

Call-note a sharp, hard tchik (repeated in alarm) or more 

liquid whit. Song a peculiarly 'mechanical' high-pitched trill of 

up to 2 mins. duration, not unlike the noise made by an angler's 

reel; often crepuscular or nocturnal. See plate Ill. 

Ageing. It is unlikely that adults moult the remiges and rectrices 

before autumn migration, so that birds with fresh wing and tail 

feathers are 1st-winter. 

Colours ofsoft parts. Bill: dark brown, lower mandible pale 

yellowish-brown. Legs: pink (not 'pale yellowish-brown' or 

'pale brown' as stated in The Handbook and other works-see 

B

ACROCEPHALUS PALUDICOLA 31 

Measurements. Both sexes. Wing, 57-67. Tail, 42-52. Bill, II-15. 

Tarsus, 19-22. See Table on pages 66,.68. Adults after breeding 

season have generally shorter wings,· 57-63, than 1st-winter 

birds, 60-67. 

Rounded tail ofpointed feathers, 8-12. 

Weight. Average offive autumn birds at British bird observatories 

12 (9-14) gm. 

Wing-formula {pp. ascendant}. Emarginated 3rd. 1st p. 4- to 2+ 

p.c. 

Wing point 3rd, often 2nd = 3rd; 4th, 2-3; 5th, 5-6; 6th, 8-9; 

7th, lQ-II; loth, 16-17. 

2nd, usually 1-2, may = 3rd, always shorter than 4th. Notch 

on inner web falls between 6th-8th. 

Moult {pp. descendant}. September adults from France and Spain are only 

partially through the post-nuptial body moult and consequently greyish-olive 

above, especially on head and nape, the new body feathers being most noticeable 

on the rufous rump and upper tail-coverts. A few have renewed the middle 

pair of rectrices, but the rest of the tail and the flight-feathers are apparently 

changed in winter quarters, and not from late June to September as stated in 

The Handbook {ii, 6o}. 

Distribution. Central Europe between the Baltic and Black Seas, extending 

westwards to W. Germany and eastwards through U.S.S.R. to Ural Mts. 

Regular as autumn vagrant to S. England; accidental Wales, Ireland, Scotland, 

Denmark, S. Sweden, S. Finland. Winters in tropical Africa. 

ACROCEPHALUS BISTRIGICEPS Swinhoe 

Schrenck's Sedge- Warbler 

A. bistrigiceps bistrigiceps Swinhoe 

Like a SEDGE-WARBLER with fairly uniform olive-brown 

upper parts, except for dark mottling on head and hind-

32 ACROCEPHALU.) BISTRIGICEPS 

sides ofbreast and flanks buff Fresh autumn dress is more rufous 

above and deeper buff below than in spring. 

Occurs in tall grasses and brush along roadsides, so is not 

restricted to marshes and rivers. 

Ageing. 1st-winter birds are like autumn adults after the postnuptial 

body moult, but the latter have remiges and rectrices 

bleached and worn. 

Colours ofsoft parts. Bill: upper mandible black, lower yellowish 

or flesh. Legs: brownish-olive or plumbeous-f1esh, soles greenishyellow. 

Mouth: yellow. Iris: greyish-hazel or dark brown. 

Measurements. Wing, 60 50-58, CjlCjl 50-56. Tail, 33 44-52, CjlCjl 

42-5 I. Bill, 12-15. Tarsus, 19-23. See Tables on pages 66, 68. 

Tail rounded, 9-13. Wing/tail ratio of 41 bistrigiceps 81-96 (cr 

tangorum). 

Weight. Shaw (1936) gives average of16 30',9.4 (8-II) gm.; 8 ¥¥ 

8 (7-10) gm. 

Wing-formula (pp. ascendant). Emarginated 3rd-5th. Long 1st p. 

3-7+ p.c. 

Wing-point, 3rd = 4th, occasionally = 5th; otherwise 5th, 

!-I; 6th, 2-3; 7th, 3-6; 10th, 7-1O!. 

2nd, 4-6, falls between 6th-8th (usually 6th-7th). Notch on 

inner web 12-13 from tip, falls about middle of ss. Notch on 

inner web of 3rd falls opposite tips of ss. Slight notch on inner 

web of 4th falls opposite loth p. Longest tertial falls short of 

loth p. 

Moult (pp. descendant). Apparently a body-moult on the breeding-growld is 

succeeded by wing and tail moult in winter quarters: I. C. T. Nisbet reports 

a complete moult in first half of winter in MalavJ. A ¥ from Yezo, Japan, 

13.ix.• is finishing pp. 8-9 and ss. 5-6, and one from 24.X. is in fresh dress. Birds 

of the typical race in winter quarters are in fresh plumage froll1 November 

January but very worn by April-Mav. 

Distribution. N.E. Mongolia and S.l:. :>lben,l tu Sakh ..diu anJ Japan, south to 

N. China and lower Yangzte Valley Winters ".I:. CiUlla and InJo-ChincsL 

countries west to S Burma 

d

ACROCEPHALUS BISTRIGICEPS 33 

A. bistrigiceps tangorum La Touche 

I consider tangorum La Touche (Central Manchuria), which is 

placed by Vaurie (1959, p. 241) as a race of A. agricola, to be a 

subspecies ofA. bistrigiceps (see page 40). Summer specimens are 

not separable 011 plumage from other populations, but the birds 

are brighter rufous above and more reddish-buff below in fresh 

autumn dress. The bill of tallgonl11l is stronger and broader, 4t-5 

wide at the base as against 4-4t in other populations, and it has 

longer and narrower rectrices. 

Measurements. Wing included with bistrigiceps. Tail, 6' 6' 45-56, 

34 ACROCEPHALUS SORGOPHILUS 

Colours ofsoft parts. Bill: upper mandible blackish-brown, edge 

ofupper and whole oflower yellow ochre. Legs: light greenishplumbeous, 

soles greenish-yellow. Mouth: yellow. Iris: ochreousbrown. 

(La Touche, 1925-30.) 

Measurements. Wing, 56-59. Tail, 46-48. Bill, 14-14t. Tarsus, 

20-21. (Three only examined). 

Wing-formula (pp. ascendant). Emarginated 3rd-5th. 1st p. t-I+ 

p.c. 

Wing-point, 4th or 3rd = 4th (in one 3rd, t). 5th, I; 6th, 4-d; 

7th, 6t-8; loth, II-I2. 

2nd, 4-5, in one just shorter and in the others just longer than 

6th. Notch on inner web 13-14 from tip, falls about middle ofss. 

Notch on inner web of 3rd falls opposite 9th-loth. 

Distribution. Said by La Touche (1925-30) to breed in ChiWi, N. China, 

and Manchuria, probably wintering S.E. China. Recorded at Luzon, Philippine 

Is. 

ACROCEPHALUS SCIRPACEUS (Hermann) 

Reed- Warbler 

A. scirpaceus scirpaceus (Hermann) 

Olive-brown above, becoming darker-especially on headwith 

wear, inclining to rufous on rump. Whitish under parts 

suffused with buffon flanks; under tail-eoverts warm buff 

Found in reed- and osier-beds and other rank vegetation and 

bushes near water; in central Europe regularly in dry situations 

in parks and gardens. Usual call-note a low churr. Song distinguished 

from SEDGE-WARBLER'S by its comparative uniformity 

and more subdued, slower delivery; a stuttering disyllabic pattern 

(ch irruc-chirruc) , but the bird will often insert into this basic 

framework a wide variety of notes, often mimetic and often 

sweet. (c. M. Swaine.) Sings at night. Good-voiced birds with 

strongly mimetic songs, occupying atypical habitats, have sometimes 

been confused with MARSH WARBLER. 

Ageing. Adults in autumn are dark olive-brown on head and 

upper mantle, and have worn wings and tail. 1st-winter birds are 

tawny-brown above and deeper buff below, except for white 

chin and throat, and have fresh wings and tail. Reddish-brown 

fringes to greater coverts contrast with blackish bastard-wing 

and primary coverts.

ACROCEPHALUS SCIRPACEUSjPALUSTRIS 37 

the proportion being very significantly greater than in adults. 

It is not known if the notch also tends to fall higher in young 

Marsh; but in any event there is clearly a danger of overlap at 

the position of notch = 8th p. 

In examining this feature the wing /Ill/st be kept closed, and not 

splayed: the 2nd p. should be drawn out from beneath the closed 

wing and allowed to lie on top of the next innermost so that the 

exact position ofthe notch can be 'read off' against the tips ofthe 

inner pp. (Compiled from a note by P. Davis, and a paper by 

J. Crudass and T. R. E. Devlin; Rye Meads Ringing Group Rep.) 

ACROCEPHALUS PALUSTRIS (Bechstein) 

Marsh- Warbler 

Greenish olive-brown above, more brownish on rump, but 

not rufous as in REED-WARBLER. Whitish below suffused with 

buff, especially on flanks; slight pale supercilium. Young are 

identical in plumage with young REED, and adults could not be 

differentiated on plumage from A. s. fusws. 

Found in damp localities with rank undergrowth, bushes etc., 

but less aquatic than REED-WARBLER, and not infrequently in 

gardens and groves. Has a churring note of higher pitch, less 

grating than SEDGE-WARBLER'S, sometimes developing into a 

rattle. Song richer and more diversified thanothers in the genus, 

'and beautiful by any birdy standards: has little of the basic 

disyllabic pattern of REED WARBLER and contains strikingly 

melodious passages in the upper register. The sweetness, continuity 

and especially the flowing quality of its delivery distinguish 

it from REED.' (c. M. Swaine.) Usually mimetic to a high degree. 

The bird is said to be bulkier-looking than REED-WARBLER (more 

like a Blackcap in stance) and often sings from a fair height in 

bushes and trees, almost always by day. 

Ageing. 1st-winter birds are tawny above, tending to rufous on 

rump: they are distinguishable from A. scirpaceus only on wingformula 

(see CAUTION under REED-WARBLER). Autumn 

adults are much worn, especially wings and tails. 

Colours ofsoft parts. Bill: dark brown, lower mandible pale 

yellowish-horn or flesh. Legs: flesh, with yellowish or brownish 

tinge, toes with a greenish tinge, soles dull yellow. Mouth:

40 ACROCEPHALL"S DUMETORUM 

Distribution. S. Finland, Baltic countries and Russia south to Ukraine, eastward 

across Siberia to Riv. Yenesei; Kirghiz Steppes, Aral-Caspian region, 

Transcaspia, E. Iran; Altai Mts eastward to N.W. Mongolia; Turkestan, W. 

Tian Shan range, Tadzhikistan, N. Afghanistan. Winters in India south to 

Ceylon, east to Assam. Vagrant to British Is at Fair Isle (Shetland), late ix. in 

1910,1912 and 1928; in 1912 there was a small influx on east coast ofEngland, 

but none has occurred in recent years despite an ;:[pparent westwards spread 

into Scandinavia. There have been several May-June records in Sweden since 

1952. Once Cyprus (Akrotiri, 14.viii.1962). 

NOTE: In the first edition, p. 40, I mentioned two specimcns which had 

bccn collected in Africa-the first for that continent-and misidentified as A. 

scirpaceus. They are from Zula, Somalia, 26.i.1952, and Bardai, Tibesti Highlands, 

Frcnch Equatorial Africa, 26.iii.1953. In recent years several birds 

believcd to bc A. dtlmetorum have been captured inspring at Lake Chad, N. 

Nigeria, by A. J. Hopson, J. H. Elgood and P. Ward (23.iii.1963), and by 

J. S. Ash, I. J. Ferguson-Lees and H. Fry in March 1967. 1. J. Fcrguson-Lees 

and I have compared one of these, togethcr with the two spccimens mentioned 

above, with raccs of the African Recd-Warbler A. baeticatus, onc of which, 

A. b. cillllamOmetls, breeds from Lake Chad north to the Sudan. This is a smaller 

bird, especially in tail and tarsus measurements, and is morc rufous than the 

specimens in question, which are closest in size and wing-formula to 

A. b. suaheliws of E. Africa, though they are olive-tinged on thc mantle and 

not foxy red as in that bird. There may well be a hitherto unsuspected 

wintering-ground ofA. dl/lnetorum in the Lake Chad region. 

THE PADDYFIELD WARBLER 

Vaurie (1959, p. 241) divides this species into three races, 

nominate agricola, brevipennis (Severtzov) and tangorum La Touche. 

The last I believe to be a race ofA. bistrigiceps (see p. 33), and for 

reasons given below I regard brevipennis as a synonym ofagricola. 

Thus, assuming there are adequate grounds for holding that A. 

concinens is specifically distinct, A. agricola is a monotypic species. 

Vaurie says the breeding range of the 'nominate' form is unknown 

but is suspected to be in India, and that it has been 

'examined from November to April from Sind, Kathiawar, 

United and Central Provinces, Southern Bombay, Mysore, 

Madras and Bhamo in Burma.' Over much the same range 

brevipennis, under which name he includes the breeding populations 

of Russia, S.W. Siberia, Turkestan etc., is also found in 

winter. Nominate agricola differs from this, he says, in being 

'more rufous above, less dull and olivaceous, more rusty, less 

whitish below'. Confusion has arisen because there are two 

colour-phases at this period, as explained below. 

A series of]une adults from the Kirghiz Steppes and Astrakhan, 

1

THE PADDYFIELD WARBLER 41 

S. Russia (as well as one from Kabul, Afghanistan), are in very 

worn dress, a greyish olive-brown above, darker on the head, and 

a bleached, pale brown on the rump. A few have already begun 

body moult, hew rufous feathers appearing on the lower mantle. 

and one from the Kirghiz Steppes is fairly well advanced. A bird 

from Baluchistan, I4.viii., and others from the United and Central 

Provinces ofIndia, in September and October, have fully assumed 

this fresh reddish-brown (agricola phase) plumage, or show a 

rather patchy mixture of these and the old grey-brown feathers. 

The great majority are at some stage ofwing and tail moult. The 

bright rufous phase does not last long, the tips soon wearing off, 

leaving the upper parts a duller and more olivaceous brown 

(brevipennis phase), with the head darker and only the rump 

retaining its tawny colour. 

Since some birds moult later than others this rufous phase 

persists in some individuals until late in the winter. As abrasion 

and bleaching proceed the body plumage becomes quite worn by 

the end of February and in March, when a pre-nuptial moult of 

the contour feathers brings more rufous into the plumage. This 

again is a fleeting phase, the tips wearing quickly during April, 

so that in late spring the plumage is already approaching the flat 

greyish olive-brown ofJune breeders from the Kirghiz Steppes. 

ACROCEPHALUS AGRICOLA (Jerdon) 

Paddyfield Warbler 

Similar to REED-WARBLER but with a more conspicuous 

pale supercilium and brighter coloration: one at Fair Isle appeared 

pale reddish-brown above and sandy-buff below'. Members of 

University College (London) S. Caspian Expedition found it 

jauntier, less sleek and shorter-tailed than REED WARBLER, and a 

warmer rufous above. (P. J. K. Burton.) 

Frequents stream and lake-sides with reeds, sedges and willows, 

also damp localities in gardens and grassy places. Call-note chikchik. 

Song not unlike MARSH-WARBLER'S but softer and without 

the harsh rattling notes. 

Ageing. Six August birds from Turkestan, young of the year 

(judging by the condition of wings and tail), have worn body 

plumage ofa paler brownish-olive than the adults. A body moult

ACROCEPHALUS ARUNDINACEUS 45 

in gardens on passage. Call-notes a harsh chak and deep churring 

croak. Song of REED-WARBLER type but louder, and with 

characteristic guttural, croaking karra-karra-karra-keek, gurk-gurkgurk 

etc., interspersed with shriller piping notes. Sometimes 

strongly mimetic, and uttered by night as well as by day, occasionally 

from high exposedperch. 

See photographs and notes by G. R. Mountfort, Brit. Birds, 44: 

195-7, plates 25-9. Also field-notes in the same journal by I. 

Houston and W. Robinson, 44: 202-4, and R. A. W. Reynolds, 

45: 220-1. See plate VI. 

Ageing. Adults have under parts sullied white in autumn, Istwinter 

suffused with orange-bufE In adults, tips to olive-brown 

scapulars, mantle and especially rump feathers are bleached and 

grey, giving a blotchy effect, whereas young are bright rusty-bufE 

1st-winter have whitish tips to flight-feathers (abraded in adults) 

and a rusty-buff suffusion on tertials and secondaries. 

Colours ofsoft parts. Bill: upper mandible dark brown, lower 

pinkish-flesh with dark brown tip. Legs: pale brownish-grey. 

Mouth: orange-red. Iris: yellowish-sepia. (The Handbook, ii, 44). 

Measurements. Wing, dd' 90-101, Sj2

ACROCEPHALUS STENTOREUS 49 

ACROCEPHALUS STENTOREUS (Hemprich and Ehren- 

berg) Clamorous Reed- Warbler 

A. stelltoreus stel1toreus (Hemprich and Ehrenberg). 

Similar to GREAT REED-WARBLER but with a different wingformula 

and more rounded tail, and an even longer bill. The 

typical race is brownish-olive above, with a rufous rump and 

pale supercilium; throat white, sometimes with a few dark shaftstreaks, 

rest of under parts warm buff. 

Habitat similar to that ofGREAT REED-WARBLER; also in coastal 

mangrove swamps. Call-note a loud repeated chak. 

Ageing. 1st-winter birds are more rufous above, more rusty-buff 

below, In autumn, adults are a worn greyish-olive on upper parts 

and show the same blotchy greyish effect as GREAT REEI:' 

WARBLER; they are whiter below and have abraded wing and 

tail feathers, whereas young birds are in fresh plumage. 

Colours ofsoft parts. Bill: upper and tip of lower mandible horn, 

rest of lower mandible pinkish-flesh. Legs; steely grey tinged 

greenish, especially on toes. Iris: pale sepia. 

Measurements. Egyptian birds. Wing, 63 78-82,

50 ACROCEPHALUS STENTOREUS l 

A. stentoreus brunnescens (Jerdon). 

The eastern form is more greyish-olive in fresh plumage, the 

difference in coloration being similar to that between REED- and 

MARSH-WARBLERS, or A. a. arul1dinaceus and A. a. zarudnyi. It is 

also whiter below than the typical race, but buffon the flanks. 

Ageing. See under stentoreus. 

Colours ofsoft parts. Bill: upper mandible blackish-brown, base 

oflower mandible flesh-pink. Legs: variously described as 'sootygrey', 

'steely-plumbeous' and'greenish-horn'; soles pale greenish. 

Mouth: bright salmon. Iris: yellowish-brown. (Ex labels, mainly 

H. Whistler.) 

Measurements. Both sexes (only 3 ¥

52 ACROCEPHALUS ORINUS 

A. s. toxopei for that matter), being a dark brown above and 

buffish-white below, heavily washed with fulvous on sides of 

breast and flanks. Perhaps the best guess is that it represents a rare 

and isolated form of the widely but very patchily distributed 

A. stentoreus. 

ACROCEPHALUS AEDON (Pallas) 

Thick-billed Warbler 

Similar to GREAT REED-WARBLER but with a thicker, shorter 

bill and much rounder wing and tail. Tail often longer than wing. 

No superciliary stripe. 

Haunts marshy places with bushes or low trees close to water; 

or on wood-edges, in gardens, by roadsides etc. Also in hazel 

thickets and thinned birch forests: in winter in tea and coffee 

plantations. Shy; raises its crown feathers into a conspicuous 

crest, and moves the tail in a shrike-like manner. Call-note a loud, 

chattering cherr-cherr-tschok. Song mimetic, beginning with 

several repeats of the tschok note, followed by a hurried chatter 

interspersed with melodious phrases and borrowings. See Neufeldt 

(1967). For a note on field-characters see K. Williamson et aI., 

Brit. Birds, 49: 89-93. See plate VII. 

The form rtifescens Stegmann, said to be darker and more 

rufous above, does not seem very satisfactory when birds from 

the same season are compared-although a critical assessment is 

bedevilled by the 'foxing' of many cabinet specimens. Measurements 

of the two forms overlap widely. 

Ageing. 1st-winter birds are rufous, with fresh wing and tail 

feathers, adults more olive, especially on mantle, and with worn 

wings and tail. 


flesh. Legs: bluish, inclining to purplish at sides, toes blue. Iris: 

olive-brown. (Own notes). Bill: upper mandible horn, lower 

yellow. Legs: variously described as greyish-brown, pale plumbeous, 

greenish-grey. Mouth: pinkish-flesh. Iris: dark brown. 

Measurements. Wing, 66 74-83,

tr 

"" 

GENUS HIPPOLAIS 55 

Plumage Variants. Very full descriptions ofadults in spring and immatures 

in autumn are given by Wallace. He also discusses plumage variations in 

individual species. The most obvious hazard to watchers and ringers is the not 

infrequent occurrence of pale icterina in which the greenish tinge of upper 

parts is suppressed and the yellow pigment almost absent beneath. Adults of 

this kind may occur at both seasons, and immatures in autumn. Similar 

'washed-out' examples occur regularly in polyglotta also, among breeding 

birds in Spain and autumn vagrants to Britain. The danger ofmis-identification 

of such 'brown-and-white' variants as pallida, or even as Sylvia borin or some 

Acrocephallls species is obvious. 

HIPPOLAIS ICTERINA (Vieillot) 

Icterine Warbler 

Uniform brownish-olive upper parts and yellow under parts, 

sides of breast and flanks slightly tinged brownish. Short yellow 

supercilium and ring round eye, and yellowish at bend of wing. 

Wing and tail feathers dark brown in fresh plumage, fringes of 

secondaries and tertials golden-yellow (adult in spring) or 

whitish (1st-winter), which together with fringes of greater 

coverts form a pale panel in the closed wing, contrasting markedly 

with the rest of the wing (see K. Williamson, Brit. Birds, 

49: 119-20). This pale panel provides the best character for 

separation in the field from MELODIOUS WARBLER (but see page 

54). As there is a complete moult late in the winter this feature 

persists well into the breeding season. 

Frequents hedgerows, woods with lush undergrowth, gardens, 

town parks etc. in both damp and dry situations. Call-notes a 

liquid, melodious diderid, a harsh Sylvia-like tek, tek and a churr 

ofalarm; also a Phylloscopus-like hooeet recorded in autumn. Song 

much like MARSH-WARBLER's, loud, vehement and varied, with 

rich musical notes freely interspersed with a discordant chatter 

and other grating noises. Often markedly imitative; occasionally 

heard by night. See plate VIII. 

Ageing. Young birds in autunm show the pale mid-wing panel, 

whereas adults do not, the remiges and coverts being very abraded. 


mandible flesh, both being yellow along cutting edges. Legs: 

blue at front, purplish-flesh at sides. Mouth: bright orange. Iris: 

dark or olive-brown. (Own notes.)

58 HIPPOLAIS POLYGLOTTA 

Wing-formula (pp. ascendant) Emarginated 3rd-5th. Long 1st p. 

3-8+ p.c., broader and rounder than in icterina. 

Wing-point, 3rd = 4th (rarely = 5th; 3rd occasionally I-I!). 

Otherwise, 5th, t-It; 6th, 2-5; 7th, 5-7; loth, 13-15. 

2nd, 4-9f, falls between 6th-7th or shorter. Notch on inner 

web, slight, 18-19 from tip, falls midway along ss. 

It will be seen that MELODIOUS has a much rounder wing than 

IcTERINE. From the proximal part of the pale panel to wing-tip 

measures about 25 in IcTERINE, and the distance between tip of 

longest tertial and wing-point equals the distance between wingpoint 

and tip oftail. In MELODIOUS the comparable buffish-brown 

panel (ifit exists) measures about 12, while the distance from tip 

of longest tertial to wing-point is only half that of wing-point 

to tip oftail. 

Moult (pp. descendant). September and October birds from Italy and S. 

France are very worn, and so is one from Uganda, 26.x. However, a bird 

from Timbuctu, I8.x., is well advanced, with pp. 8-9 growing and the rest, 

plus ss. 1-2, tertials and tail, new. (This is at the same stage as an ;cter;na from 

S.E. Congo dated I8.i., indicating a difference of some three months in the 

timing of the moult.) One from Nigeria, IS.xii. is complete except for short 

ss. 4-6. Other December birds from Ivory Coast round to Nigeria are in fresh 

plumage, and the moult is obviously very early, in all probability beginning 

as soon as the birds reach the wintering area. March examples are already 

looking rather worn, and many (though not all) spring migrants are well worn 

by the time they arrive on the breeding-grounds (cf. H. ;cter;na). 

Distribution. Iberian Peninsula, France (except N. and E.), S. Tyrol, Italy 

and N. Africa, wintering W. Africa from Senegal to Cameroons. Of regular 

occurrence S. England and Irish Sea basin, twice only Scotland (Is. May, 

27.ix.I9I3; Fair Isle, I6.ix.I9SS). There was a remarkable number of occurrences-over 

S0-at Irish Sea and English Channd bird observatories in 

autumn 1962. 

IDPPOLAIS PALLIDA (Hemprich and Ehrenberg) 

Olivaceous Warbler 

H. pallida opaca Cabanis 

H. pallida elaeica (Lindermeyer) 

The two races most likely to occur in Britain are opaca (southern: 

Spain and N. Africa) and elaeica (eastern: Balkans, Asia Minor, 

d

HIPPOLAIS OLIVETORUM (Strickland) 

Olive- Tree Warbler 

Brownish-grey above, with slight whitish supercilium and eyering. 

Under parts white, suffused with pale yellow on the breast 

and greyish on the flanks. White fringes to tertials and secondaries 

form a light mid-wing panel as in 1st-winter IcTERINE: this 

persists in adults until about mid-June. Outer tail-feathers have 

white margins, and these and the penultimate feathers a white 

crescent at tip. 

Frequents open canopy oak-woods, olive groves, orchards. 

Shy and secretive. Song resembles SEDGE-WARBLER'S in loudness 

and rapidity but is superior in tone. 

In· size and tone of plumage this bird resembles 1st-winter 

BARRED WARBLER Sylvia nisoria. However, I. J. Ferguson-Lees, 

P. A. D. Hollom and R. Spencer, who met with both species 

in Bulgaria, emphasize that its greyness, large size and heavy 

build, and especially its enormous bill, make olivetorum a very 

distinctive species. Compared with BARRED WARBLER it has a 

proportionately shorter tail and noticeably larger body, whilst 

the long dagger-like bill (thick with curved culmen in nisoria) 

recalls that of GREAT REED-WARBLER; also 1st-winter BARRED 

has buff tips to greater and median coverts. In the hand, wingformula 

and bill-measurement should suffice, and a further 

difference is that the white mark at the tip of the outer tailfeathers 

is half-moon shaped in olivetorum and wedge-shaped in 

nisoria. 

Other features stressed by the above observers (in litt.) are: 

secondaries with pale whitish outer webs forming a prominent 

whitish panel on closed wing at rest (but not noticed in flight); 

pale supercilium extending behind eye; crown slightly peaked at 

rear; under parts greyish-white, not noticeably buffer on breast. 

Ageing. 1st-winter birds are rather more olive above than adults, 

and have fresh wings with the whitish mid-wing panel. There is 

no yellow on under parts or at bend of wing as in IcTERINE. 

Colours of soft parts. Bill: upper mandible dark brown, lower 

yellowish. Legs: bluish-grey. (Ex labels.) Bill: pale horn-brown, 

yellowish at base and along cutting-edges. Legs: dull pale bluish 

.grey. Eye: dark. (Above-named observers.) 

63 

_

- --------------- ., 

TABLS I-continued 

MBASURl!MBNTS-WING AND TAIL 

WING TAIL 

theoretical theoretical 

SPECIES/RACE n. mean s.d. range n. mean s.d. range 

dumetorum 117 61.22 1.56 56--- 66 116 51.94 2·09 45-58 

agricola " 66 57. 18 2.00 51- 63 67 54·36 3. 10 45-64 

concinens .. 35 55·17 1.65 50- 60 34 56·09 2·37 49-63 

arundinaceus 96 94.61 3.03 85-1°4 97 77·59 3·08 68-87 

zarudnyi 39 95·59 2·74 87-1°4 36 78.22 3·53 67-89 

orientalis 52 81.98 3·37 72- 92 51 70·75 3·04 61-80 

griseldis .. 10 80.60 2·55 73- 88 9 63.67 3·12 54-72 

stentoreus 14 78.14 2·57 70- 86 IS 74·60 3·16 65-84 

brunnescens 32 86.88 2·54 79- 95 33 79·33 3.70 68-91 

aedon 77 78.66 2.41 71- 86 66 84.26 3.23 74-94 

icterina .. 85 76.87 2.48 69- 85 85 52.82 2.23 46-60 

polyglotta 88 64·69 1.68 59-70 88 50.65 1.85 45-57 

opaca 55 68.18 2.16 61-75 52 57·37 2·55 49-65 

elaeica 86 65·86 1.92 60-72 84 52·99 2.00 47-59 

caligata 5° 59.60 1.62 54- 65 50 47.90 2.07 41-54 

rama 54 60.61 1.65 55- 66 49 53·16 2·47 45-71 

olivetorum 31 85·71 2.18 79-93 31 67·55 2·73 59-76 

languida .. 32 74·81 2·09 68- 81 3° 61.63 2.03 55-68 

'" -..,J

TABLE II-continued 

MEASUREMENTS-BILL AND TARSUS 

BILL TARSUS 

theoretical theoretical 

SPECIES/RACE n. mean s.d. range n. mean s.d. range 

dumetorum 43 16.65 0.62 141-181 22 22·50 0.65 201-241 

agricola 34 14.67 0.18 131-16 17 21.68 0.96 181-241 

concinens 31 14·69 0.18 14 -16 10 21.85 0.13 21 -221 

arundinaceus 95 22·35 1.03 19 -251 (J9 29.88 1.18 26 -331 

zarudnyi 39 22.26 0·94 20 -25 32 29.81 1.00 27 -33 

orientalis 47 21.77 1.20 18 -251 33 28.85 1.20 251-321 

grise1dis 10 21.80 0·79 191-24 9 25.22 0.83 221-28 

brunnescens 24 23.83 0·96 21 -27 17 29·88 1.11 261-331 

aedon 73 18·45 0·53 161-20 50 28.18 1.26 241-32 

icterina 61 16.20 0·73 14 -181 19 21.32 0·75 19 -231 

polyglotta 35 15·54 0.83 13 -18 15 21.33 1.00 181-241 

opaca 68 17·90 0·46 161-191 25 23·32 0.63 21!-251 

elaeica 47 15·93 0.81 131-181 13 21.85 0.83 191-241 

caligata 44 13.15 0·51 111-141 

21 21.05 0.86 181-231} 

rama 51 14.69 0.70 I21-161 

olivetorum 31 19·47 0.81 17 -22 31 24.08 0·91 211-27 

languida 29 17.60 0·57 151-191 12 22.92 0.67 21 -25 

$

70 

USING THE KEYS 

Two main keys are given below, one for the genera 

LOCUSTELLA and ACROCEPHALUS combined, the 

other for the genus HIPPOLAIS. Before using them it is 

therefore necessary to be sure to which genus one's bird 

belongs, and to facilitate this decision an introductory 

key to all the genera has been provided. It will also help 

the user ifhe bears in mind that in general the tail is much 

more rounded in LOCUSTELLA than in the streaked 

ACROCEPHALI (though melanopogon is an exception); 

and that the tail is almost square in most HIPPOLAIS. 

The monotypic genera LUSCINIOLA and PHRAGA 

MATICOLA are here included with ACROCEPHALUS 

(see p. 9). 

Because the plumage differences between species, in many 

cases, are less marked than the variations within species due 

to age or season, geographical distribution and even individual 

variation, it has been necessary to base the keys 

primarily on structural characters, particularly wingformula. 

In some cases the distinctions are very fme, and 

always the greatest possible care must be taken in measuring. 

Even so there are undoubtedly a few cases (e.g. young 

RE1ID--and MARSH-WARBLERS, perhaps small GRASSHOPPERand 

large LANCEOLATED WARBLERS) for which the keys will 

not work. 

Because of the fine degrees ofdifference usually involved 

I have often cited several characters (in order ofusefulness) 

where such exist; nevertheless, it is necessary to warn the 

user that no bird should be determinedfrom the keys alone. When 

an opinion has been formed on the basis of the keys, the 

user must turn to the appropriate species in the text and 

check the result against the wider range of information 

available there. 

_________________d

KFY to the genera CETIIA, LOCUSTELLA, ACROCEPHALUS and HIPl'OLAIS 

A. Tail with ten rcetriccs CETTlA 

B. Tail with twdve rcetriccs 

B.x Upper parts streaked or mottled 

No head-pattern, supercilium indistinct 

Pronounced head-pattern, supercilium well-marked 

B.2 Upper parts uniformly some shade ofbrown or olive 

Outer and penultimate rcetriccs with white spots 

Outer and penultimate rcetriccs without white spots 

Bend ofwing with yellow 

Bend ofwing without yellow 

., 

LOCUSTELLA 

ACROCEPHALUS 

HlPPOLAlS 

HlPPOLAIS 

ACROCEPHALUS

KEY to the genera LOCUSTELLA and ACROCEPHALUS 

A. Uniformly dark-brown or olive-brown upper parts 

3rd-4th (sometimes also 5th) pp. emarginate 

Wing longer than 70 

Bill slender, 22-25, 1st p. minute; tail 84-96% ofwing-length 

Bill robust, 17-20; 1st p. very long; tail 102-114% ofwing-length 

Wing shorter than 70 

Supercilium slight; notch inner web 3rd p. = 8th/loth 

Supercilium prominent; notch inner web 3rd p. = ss. tips 

2nd p. = 5th/8th; 6th p. not emarginate 

2nd p. = 8th/loth; 6th p. sometimes emarginate 

3rd p. only emarginate 

Wing longer than 75 

Throat feathers with pale brown streaks 

Notch inner web 2nd p. = 6th/8th; legs brownish 

Notch inner web 2nd p. = 8th/ss. tips; legs bluish-grey 

Throat feathers without brown streaks 

Tail markedly rounded, 22-25 

Tail slightly rounded, 5-9 

Wing shorter than 75 

2nd p. = 5th/6th 

2nd p. = 3rd/5th 

Notch inner web 2nd p. higher than 8th 

Notch inner web 2nd p. lower than 8th 

pp. not emarginate 

Under tail-coverts buff-brown tipped white; throat mottled dark brown 

Under tail-coverts whitish tipped buff; throat uniformly white .. 

stentoreus races 

aedon 

dumetorum 

agricola 

concinens 

arundinaceus, zarudnyi 

orientalis 

fasciolata 

griseldis 

pleskei 

scirpaceus, Juscus 

palustris 

.fluviatilis 

luscinioides, fusca

KEY to the genw HIPPOLAIS 

A. Outer and penultimate: tail-feathers with white tips; no yellow at bend ofwing 

pp. 3rd-4th emarginate 

2nd p. = 4th/Sth; notch on inner web 2nd p. = 8th/10th; wing 82-90. 

2nd p. = Sth/7th; notch on inner web 2nd p. falls below ss. tips; wing 72-79. 

pp. 3rd-sth emarginate 

Bill strong, IS-19 ; wing 62-72. 

2nd p. = 6th/7th, bill-width at nostrils 4-sl . 

2nd p. = 7th/8th, bill-width at nostrils s-6l . 

Bill weak, 12-14 ; wing S7-64 

B. Outer and penultimate tail-feathers without white tips; yellow at bend ofwing 

Tail6s-73% ofwing-length; 2nd p. = 3rd/Sth; 1St p. less than 3+ p.c. . . 

Tail 74-83 % ofwing-length; 2nd p. = 6th/8th; 1St p. more than 3+ p.c... 

olivetorum 

languida 

elaeica, pallida 

optUa 

caligata. rama 

icterina 

polyglotta

I 

ACKNOWLEDGEMENTS 

The information presented here has been gained almost entirely 

from a study of the skins in the national collection, and I am 

grateful to Mr. J. D. Macdonald, Keeper of Birds at the British 

Museum (Natural History), for the facilities he has afforded me, 

and also to his staff at the Bird Room for their kind assistance. 

Some work was also done at the Royal Scottish Museum, 

Edinburgh, and for facilities there I am indebted to Mr. Rodger 

Waterston and his staf£ I am also glad to have had opportunities 

for frequent discussion of various problems with Mr. Robert 

Spencer, the Ringing Officer of the B.T.O., and have received 

much encouragement and advice from the members of the 

Nuffield Grant Committee ofthe B.T.O. 

An important aim in planning this Guide was to make the 

section on measurements as comprehensive, and therefore as useful 

to the field-worker, as possible. This could not have been done 

without the willing and invaluable help on the statistical side 

given by Mr. Timothy Bagenal and his assistant Miss Sheila 

Morris, of the Marine Station, Millport, Isle of Cumbrae. I am 

most grateful to them for their interest and help. 

I am grateful to those in charge ofthe various bird observatories 

and ringing stations for sending me records of bird weights and 

other useful data. 

I am greatly indebted to Robert Gillmor for the handsome 

cover and title-page designs, and to Eric Hosking and C. C. 

Doncaster for their kindness in presenting the photographs which 

appear as plates I, Ill-VI and VIII. Two additional photographs, 

plates 11 and VII, ofL.fasciolata and A. aedon nesting in Amurland, 

were very kindly presented by Miss Irene Neufeldt ofthe Leningrad 

Academy of Sciences. My thanks are due to I. J. Ferguson 

Lees for his assistance in several respects, and to H. F. and G. 

Witherby Ltd., the publishers of British Birds, for lending the 

block ofthe Icterine Warbler. Finally, it is a pleasure to acknowledge 

the personal interest and expert help afforded by the 

staffofthe Holywell Press while the Guide was with the printers. 

75

76 

REFERENCES 

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and distribution. Bull. Mus. Comp. Zool., 190: no. 4. 

BROWNE, K. and E. (1956). An analysis of the weights of birds trapped on 

Skokholm. Brit. Birds, 49: 241-257. 

CORNWALLIS, R. K. and SMITH, A. E. (1960). The Bird i" the Hatld. 

Field-guide no. 6 of the British Trust for Ornithology, Oxford. 

DRESSER, H. (1902). A Manual ofPalaearctic Birds. London. 

FIlTER, R. S. R. and RICHARDSON, R. (1952). The Pocket Guide to 

British Birds. Collins, London. 

GLADWIN, T. W. (1963). Increases in the weights of Acrocephali. Bird 

Migration, 2: 319-324. 

HARTERT, E. (1910). Die Viigel der paliiarktischen Fauna. Band 1. Berlin. 

HOLLOM, P. A. D. (1952). The Popular Handbook ofBritish Birds. Witherby, 

London. 

HOLLOM, P. A. D. (1960). The Popular Handbook of Rarer British Birds. 

Witherby, London. 

KLUZ, Z. (1943). Omithologicke Tabulky. Ochralla Rostlin, XVIII. Prague. 

LA TOUCHE, j. D. D. (1925-30). A Handbook of the Birds o{ Easterl/ China. 

Vo!. 1. London. 

MEINERTZHAGEN, R. (1954). Birds ofArabia. Oliver and Boyd, Edinburgh. 

NEUFELDT,I. (1967). Studies ofless familiar birds. 144. Thick-billed Warbler. 

Brit. Birds, 60: 239-243. 

NISBET, I. C. T. (1967). Migrrtion and moult in Pallas's Grasshopper Warbler. 

Bird Study, 14: 1)6-103. 

PARKER, S, A. and HARRISON, C. j. O. (1963.) The Validity of the 

genus Lusciniola Grey. Bull. B.O.C. (in press). 

PARSLOW,j. L. F. (1967). Changes in status among breeding birds in Britain 

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77

78 

ACROCEPHALUS 5, 9, 10, 25-53. 

54, 55, 70, 71, 72, 76. 

aedon 52-53. 67, 69, 70, 72, 75· 

agricola 33,40,41-42. 43, 67, 69, 72. 

alaris 56. 

albiventris 12, 66. 

amyae 51. 

annedens 61, 62. 

arundinaceus 44-48. 49, 50,67,69, 72. 

baeticatus 40. 

bistrigiceps 31-33. 40, 66, 68, 73borin 

54, 55, 65· 

borisi 56. 

brevipennis 40. 

brunnescens 44, so. 67, 69. 

caligata 53, 54, 61-62. 67, 69, 74· 

centralasiae 22, 23. 66, 68. 

certhiola 21-23. 24, 25, 66, 68, 73. 

cetti 11-12. 66, 68. 

CETTIA 11-12. 71,77. 

cettioides 12. 

cinnamomeus 40. 

concinens 40, 42-43. 51, 67, 69, 72. 

dumetorum 39-40. 67, 69, 72. 

elaeica 58-60. 67, 69, 74· 

fasciolata 15, 16-17.66, 68, 72, 75. 

fluviatilis 14-16. 17,66, 68, 72. 

fusca I" 72. 

fuscus 35, 36. 38, 72 • 

gigantea 20. 

griseldis 44, 45, 48. 67, 69, 72. 

haringtoni 43. 

HIPPOLAIS 5, 10,53-65.70,71, 

74,n 

icterina 54, SS-56. 57, 58, 64, 67, 

69,74· 

laeneni 60. 

lanceolata 19-20.66,68, 73. 

languiJa 6.1-65.67,69,74. 

LOCUSTELLA 5, 9, 13-25.70, 71, 

72,77. 

INDEX OF SCIENTIFIC NAMES 

luscinioides 13-14. 66, 68, 72. 

LUSCINIOLA 9, 70, 76. 

melanopogon 9, 25-28. 66, 68, 70, 73. 

mimica 26, 27-28. 66, 68, 73. 

minor 23. 

mongolica 19. 

naevia 17-19. 66, 68, 73. 

nisoria 63, 64. 

obscurior 19. 

ochotensis 21, 22, 23, 24-25.66,68, 73. 

olivetorum 540/56, 63-64. 67, 69, 74. 

opaca 58-60.67,69,74. 

orientalis 12, 44,45, 47-48.51,67,69,72. 

orinus SI. 

pallida 54, 55, 58-60. 62, 74. 

paludicola 30-31. 66, 68, 73. 

palustris 36, 37-38. 66, 68, 72. 

PHRAGAMATICOLA 9, 70. 

PHYLLOSCOPUS 5, 7, 9, 55, 61, n 

pleskei 21, 24, 25, 72. 

polyglotta 54, 55, 56, 57-58. 67, 69, 74. 

rama 61-62.67,69, 74. 

reiseri 60. 

rubescens 21-23. 66, 68. 

ruJescens 52, 53. 

schoenobaenus 28-30.66, 68, 73. 

scirpaceus 34-36. 37, 40, 66, 68, 72. 

sorgophilus 33-34. 73. 

sparsimstriata 23. 

stentoreus 44, 48, 49-51. 52, 67, 70, 72. 

stevensi 43. 

straminea 18-19.66, 68, 73. 

styani 25. 

suahelicus 40. 

SYLVIA 54, 55, 63, 65. 

tangorum 32,33.40, 66, 68, 73. 

toxopei 51, 52. 

zarudnyi 44,45,46,47.50,67,69.72. 

g

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Warbler - British Trust for Ornithology

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