Hooded Crow Corvus cornix Scientific name definitions

Taxonomic note: Split. This account was originally published under a single species in HBW Alive, but in Birds of the World it covers multiple species. We present that original content here, with the goal of developing a more refined species account for this taxon moving forward. Please consider contributing your expertise to update this account.

48–54 cm; 396–602 g. Size, structure and habits are basically as for C. corone. Nominate race has black hood formed by glossy black crown , upper nape, side of head, throat and "breastplate" (lower border of breastplate somewhat irregular); tibia and both wing surfaces and tail also black, and uppertail-coverts variably blotched blackish and gray; rest of plumage, including nape, side of neck, mantle, scapulars, rump and some uppertail-coverts, remaining underparts and axillaries ashy gray with fine dark shaft streaks; through wear, black areas of plumage become dull and unglossed; iris dark brown; bill black; legs dark gray. Sexes similar. Juvenile  has duller and rather looser, softer, more brown-toned gray plumage than adult, lacking dark shaft streaks on body feathering, also has grayer iris and pinkish-red interior of mandibles (dark gray in adult), and may show pale or fleshy gape-flanges into first autumn. Races differ mainly in size and plumage tone, variation chiefly clinal: <em>sharpii</em> is paler gray than nominate, W birds tending to be larger than those in E; <em>pallescens</em> is smaller and even paler gray than previous; capellanus is distinctive, large and stout-billed, with extremely pale gray body plumage, appearing almost black and white in the field (especially when plumage worn). Hybrids with C. corone variable, some being like present species but with blackish markings on mantle or lower underparts, others almost wholly black with scattered gray feathers on mantle and breast.

Thought to form a superspecies with C. corone, possibly also including C. pectoralis; was for long treated as conspecific with former. Situation complex, as narrow bands of hybridization between present species and C. corone exist across Scotland, through C Europe, in C Siberia and in C Asia (1 Vijay, N., C. M. Bossu, J. W. Poelstra, M. H. Weissensteiner, A. Suh, A. P. Kryukov, and J. B. W. Wolf (2016). Evolution of heterogeneous genome differentiation across multiple contact zones in a crow species complex. Nature Communications 7:13195. Close 2 Kroykuv, A. P. (2019). Phylogeography and hybridization of corvid birds in the Palearctic Region. Vavilov Journal of Genetics and Breeding 23:232-238. Close ), but striking plumage differences resulting from different melanistic phenotypic expressions, subtle differences in vocalizations, and both narrowness and plasticity of hybrid zones all suggest that speciation has been at least partially achieved, even if very recent in evolutionary time scales (2 Kroykuv, A. P. (2019). Phylogeography and hybridization of corvid birds in the Palearctic Region. Vavilov Journal of Genetics and Breeding 23:232-238. Close ). British Is present a most interesting distributional jigsaw, with present species throughout Ireland, I of Man, N Scotland and Scottish isles, being replaced by C. corone over England, Wales and S Scotland; this suggests that present species had colonized from E, probably being the original British crow, but N-spreading C. corone from France or Spain colonized S England; meanwhile, Ireland and I of Man had separated from mainland Britain before England became separated from continental Europe. The spread continues today, with Scottish band of hybrids creeping N as black-plumage genes obliterate grey genes. Nominate race intergrades with sharpii in region of Urals. In E Europe and W Asia there is a cline of increasing paleness and smaller size from N to S, but complicated by bleaching, and several other described races are best treated as synonyms: thus, khozaricus (described from S Russia) is synonymized with nominate, and kaukasicus (Caucasus region), sardonius (Sardinia), italicus (Italy) and minos (Crete) are treated as synonyms of sharpii. Extreme S race, pallescens, is at palest end of cline, is relatively small and rather weak-billed, and contrasts markedly with the almost black-and-white, large-billed capellanus of Iraq and extreme SW Iran. capellanus is distinct in its plumage and geographic range, and it may represent a separate species or semi-species, as suggested by some authorities (e.g. OSME ORL), suggesting that latter may well have evolved to full species level. Four subspecies recognized.

• Carrion x Hooded Crow (hybrid) Corvus corone x cornix

Editor's Note: Additional distribution information for this taxon can be found in the 'Subspecies' article above. In the future we will develop a range-wide distribution article.

Open country with at least scattered trees. Favours mixed farmland, parks and gardens, from city centres to forest clearings, and equally at home on moorland as it is on inshore islands, coastal cliffs and estuarine flats. Tolerates humans more so than does C. corone, being far more approachable and quite numerous in the streets of many cities. With encroachment of cultivation into the desert (e.g. in Israel), it has now come into contact with C. ruficollis, but it keeps very much to lusher areas of cultivation and does not tolerate true arid conditions. Breeds at up to 1350 m in the Tatra Mts (Poland-Slovakia); recorded to 1000 m in the Carpathians and the Urals, 1125 m in the Altai and 2050 m in the Saraibulag Range of Armenia. In hybrid/overlap zone in E Alps, there is a tendency for C. corone to occupy higher elevations than the lowland-haunting present species.

Resident in W & S; N and interior birds move S in autumn (Sept–Nov) to varying degrees, many remaining about towns and settlements even in far N in milder winters. Birds from Scandinavia and E to C Finland winter in countries bordering S coast of North Sea, those of E Finland wintering chiefly NE Germany and N Poland. Formerly substantial numbers wintered across W Europe to N France and E England, but far fewer have done so in recent decades (presumably because birds remain in towns and villages in breeding areas). Breeders from W Russia E to the Urals move S to Volga Delta and nearby steppes; those from farther E migrate to Kazakhstan , Turkmenistan and Afghanistan, a few reaching Pakistan, W China (Xinjiang) and extreme NW India. Vagrants reported from Greenland, Jan–Mayen, Bear I, Iceland, Svalbard, Novaya Zemlya, Malta, Tunisia and Libya, most of which referable to overshooting on spring migration (Mar–May). At migration times, can assemble in thousands at key points.

Omnivorous  , but chiefly a carnivorous scavenger  . Diet varies according to local situations and season, but basically invertebrates , especially earthworms (Lumbricidae) and insects, also small mammals, frogs, bird eggs and nestlings, and carrion; also takes small amounts of grain and weed seeds. Molluscs may constitute a significant part of the diet, at coastal areas (3 Berrow, S.D., Kelly, T.C. and Myers, A.A. (1992). The diet of coastal breeding Hooded Crows Corvus corone cornix. Ecography. 15(4): 337–346. Close ) and in some lowland river valleys (4 Gołdyn, B., Książkiewicz-Parulska, Z. and Zduniak, P. (2016). Freshwater molluscs in diet of Hooded Crow (Corvus cornix). Wilson J. Orn.. 128(2): 459–462. Close ). Fledglings fed almost entirely on insects through early summer, switching to higher levels of grain and weed seeds in autumn and winter. Forages almost entirely on ground , turning over seaweed, dung or stones to get at insects and other invertebrates; chases other birds to make them drop or regurgitate food items. Pairs patrol roads and tidal shorelines for carrion, or forage along lakeshores, across mudflats and along seashores, searching for dead or live food items. Sociable, in pairs and small groups; sometimes larger flocks. Roosts singly, in pairs or in small to large gatherings (up to several thousand, especially in winter), usually in trees or on cliff faces, but in open areas among heather on open moorland.

Much as for C. corone, but a certain amount of regional variation of a fairly varied vocabulary complicates interpretation of differences. Most frequently heard call a slightly softer, more rolling "aaarrr", less hoarse than that of C. corone; some evidence to suggest that some basic vocalizations may have different meanings for the respective species. Race capellanus said to have a deeper and gruffer voice than others.

Season commences late Mar in Britain, peak egg-laying mid-Apr; at S limit of range, eggs from end of Jan in Egypt, Feb in Israel and Persian Gulf, mid-Mar in Iraq (capellanus) and Georgia; oddly, laying said to be in May in Greece; farther N, laying begins in mid-Apr in N Caspian region and N Caucasus foothills, about third week in Apr in Moscow region, and May in Finnish Lapland; single-brooded. Monogamous long-term pair-bond, partners keeping together through most of year, but bond less strong when flocking. An instance of apparent communal breeding has been reported for Scotland, where in 2011 nine eggs were laid in a single nest and the territory was occupied by a trio of birds that engaged in territory defence as a group (5 McIvor, G.E. and Healy, S.D. (2015). Communal nesting by Hooded Crows. Bird Study. 62(3): 423–426. Close ). Solitary breeder, although generally more sociable than C. corone even in breeding season, when can form loose colonies; inter-nest distance 20 m in parts of Moscow. Nest built by both sexes, often female doing construction whilst male collects materials , fresh nest can be built in 7–8 days; rather bulky, based on sticks and twigs  , often mixed with animal bones, sheep wool and heather, mud pushed into base to give it a solid foundation, deep cup thickly lined with soft materials such as wool, fur, soft grasses and the like, usually placed in crown of tall tree; normally fresh nest built each year, but in some places where availability of sites is limited an old nest may be repaired and reused; in more open habitats electricity pylons provide nest-sites, and on exposed coasts a cliff ledge or stunted shrub may be used; some nests built on old buildings or even on the ground, sheltered by heather, a stone wall or rocks. Clutch usually 4–5 eggs ; incubation by female, period 17–20 days; chicks fed by both parents, nestling period 3–5 weeks; young somewhat dependent on parents for a further 2–3 weeks and often throughout first winter; in late summer family unit normally breaks up as juveniles join foraging flocks, either with or without adults. Nest occasionally parasitized by Great Spotted Cuckoo (Clamator glandarius) in E Mediterranean region. Capable of breeding at 2 or 3 years of age.

Not globally threatened. Abundant, with apparent population increases over recent decades in most European countries, most notable being its spread into cities from the countryside. Densities vary with location; in Moscow city area as high as 32–36 pairs/km², whereas in agricultural land nearby only c. 2–3 pairs/km². Reports from Egypt indicate a dramatic decline in populations of Nile Delta, which could be linked to pesticides. Following estimates (pairs/territories) have been made for most countries within W Palearctic: Faeroe Is 500–1000, Scotland & I of Man 160,000 (plus 20,000 hybrids), Ireland 290,000, Germany 63,000–84,000, Denmark 21,000–220,000, Norway 200,000–600,000, Sweden 250,000–500,000, Finland 200,000–300,000, Estonia 50,000–100,000, Latvia 20,000–60,000, Lithuania up to 70,000, Poland 50,000–100,000, Slovakia 15,000–30,000, Hungary 70,000–80,000, Italy 110,000–520,000, Greece 150,000–200,000, Albania 10,000–30,000, Croatia 110,000–150,000, Slovenia 8,000–12,000, Bulgaria 500,00–1,000,000, Romania 30,000–50,000, Russia 1,000,000–10,000,000, Belarus 280,000–320,000, Ukraine 450,000–500,000, Moldova 7000–10,000, Azerbaijan 8000–10,000, Turkey 100,000–1,000,000, Israel c. 200,000, Egypt 10,000–100,000. Has long been persecuted by gamekeepers and farmers owing to its egg-stealing and nest-robbing habits; over much of its European range, however, it is now increasing, finding that city and town parks as well as rubbish dumps provide not only easy scavenging, but also habitats safer from human persecution.