Large-billed Crow Corvus macrorhynchos Scientific name definitions

46–59 cm; 450–1000 g; wingspan 100–130 cm. A medium-sized to large crow, varying much in size, with relatively long, dagger-like bill with somewhat arching culmen (most marked in males of the N races), base of culmen concealed by overlapping bristles. Nominate race has distinctly peaked forehead, plumage entirely black, head, neck and upperparts, including wing and tail, strongly glossed, upper surface of wing and central tail feathers shot with purple; underparts black with strong sheen; bases of neck feathers pale grey, throat feathers with notched hackles (giving somewhat jowled appearance); iris dark brown; bill (60–69 mm) and legs black. Distinguished from very similar C. enca by concealed culmen base, in flight by relatively longer tail with more graduated tip, wing with longer hand and more obviously fingered primaries. Sexes similar, female on average smaller than male, with less arched culmen and less strongly graduated tail. Juvenile has softer and less glossy plumage than adult, with matt black underparts, lacks throat hackles, has inside of mandibles reddish-pink (black in adult), iris smoky blue. Races differ in bill size, also in overall size and degree of gloss in plumage: japonensis is largest, has largest bill (70–80 mm) with almost ridged arch on culmen, dusky-grey bases of neck feathers and highly glossed plumage; connectens is similar to last but smaller (bill 62–69 mm); osai also is similar but bill smaller (55–59 mm); mandshuricus is only a little smaller than japonensis, has duller plumage, bill shorter (60–68 mm) but deeper and more highly ridged; colonorum is similar to japonensis but smaller (bill 57–61 mm), with duller neck and underparts, less purple in gloss of wings and tail; tibetosinensis is large (bill 60–73 mm), very black and glossy, and has variable whitish to dark grey bases of neck feathers; intermedius is large (bill 54–73 mm), dull greyish-black in colour, with bill somewhat slimmer, and has whitish bases of neck feathers; philippinus is close to nominate race in plumage, but has whiter bases of neck feathers and relatively longer tail; levaillantii is wholly glossy black, with bases of neck feathers dusky grey, bill 61–69 mm, rather deeper than the next; culminatus is small and rather glossy black, with slimmer bill than other races (bill 52–67 mm).

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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.

Forests and woodland of all types across its wide range. In far N (in Amurland and on Sakhalin) chiefly by rivers and their floodplains in forests of the taiga, gathering by villages and settlements, particularly in winter. Reaches 2000 m in Sri Lanka, 2300 m in Nilgiris of S India and 4500 m in Sikkim. In Himalayas ranges to upper limits of tree-line and beyond, following yak (Bos grunniens) and pony caravans high into mountains; has reached 5000 m on Tibetan Plateau and been recorded following mountaineers on Everest as high as 6400 m. N populations forsake frozen interior in winter and congregate by river mouths and seashores. Farther S in Asia can often be found alongside the more numerous C. splendens in towns and cities; far less closely associated with man than is latter, but each little village with a large tree usually has a nesting pair of present species. Parties converge and flock to large trees, particularly those close to slaughterhouses, rubbish dumps and small fishing ports. In tropical Asia its habitats are similar to those in the far N, but may often be found in more or less semi-open agricultural land, with scattered trees. Favours forest edge and clearings, paddyfields and coconut (Cocos nucifera) plantations, especially by rivers and in coastal lowlands, including mangroves and wooded inshore islands. Where range overlaps with that of C. enca, latter seems unable to compete successfully with present species and becomes an inconspicuous crow of dense lowland forests.

Generally regarded as sedentary, but presumably wanders to a degree; sporadic observations on several islands of Japan, Indonesia and Philippines. In far N, Amurland, Kurils, Sakhalin and Hokkaido, many move out of the hostile interior in winter to coastal waters, particularly ice-free river mouths.

Omnivorous scavenger. Takes carrion of all kinds, by foraging along shorelines and roadsides, stealing food items from vulture nests (food brought in by parent vultures to feed their young). Robs bird nests of both eggs and fledglings. Feeds with vultures on animal carcasses, kills rodents and palm-squirrels (Funambulus), lizards (Colotes), frogs, large invertebrates including crabs, centipedes (Chilopoda), grasshoppers and locusts (Orthoptera), moths and caterpillars (Lepidoptera), beetles (Coleoptera), ants (Formicidae) and termites (Isoptera); clumsily hawks for winged termites and even small bats in flight. Also takes variety of fruit, both wild and cultivated, including berries and cherries; variety of cereals (e.g. Sorghum, Oryza, Pennisetum, Triticum, Zea), seen to wrench off whole maize cobs and digs up groundnuts (Arachis). Clumsily feeds among foliage of a variety of flowering trees (e.g. Bombax, Erythrina, Butea, Grevillea, Spathodea), taking both nectar and petals. In Japan, a bird feeding young was seen to hide food items during early-morning foraging, returning later to feed both young and sitting partner on nest. In N India one was watched as it hammered a concealed object, possibly a nut or a pine cone, with a stone. Usually encountered in pairs or family parties, often feeding with other birds in fruiting trees; larger congregations at good food sources. In Himalayas, follows herds of goats and sheep high into their summer pastures.

In need of comparative analysis. Complex, with degree of variation within vocabulary of each taxon. All have reasonably similar cawing note which varies in hoarseness, intermedius has loud, dry "kaaa-kaaa", stronger and lower in pitch than that of culminatus, some calls of intermedius are quite musical and include single weak croak which lacks deep croaking resonance of the "prruuk-prruuk" of C. corax. Tibetan race tibetosinensis has low-pitched and rather hoarse "keearrh-keearr". Philippine philippensis gives loud, guttural "weerrk-weerrk-weerrk", the notes deeper and more spaced in delivery than those of C. enca. Race levaillantii said to give distinctive nasal yapping, with duck-like quality, each note rising and falling suddenly, "nYArk, nYArk", while those on Andamans are said to utter calls which are more plaintive and less harsh than those of culminatus. Nominate race has relatively low-pitched and gruff caws, and also gives deep gargling rattle in flight. Race japonensis patrolling territory utters "kroo-kroo" or "krau-krau". As is evident, it is difficult to decide on precise vocal differences between taxa on basis of transcriptions alone, especially when range of calls of each taxon not well known (e.g. the well-studied Indian culminatus is known to have at least ten distinct calls).

Egg-laying begins at almost any time of year over such an extensive range. Eggs recorded late Apr in Amurland (mandshuricus), early May on Kuril Is and from late Apr on Hokkaido (japonensis), early Mar on Okinawa (connectens), Mar–Jun on Negros and Aug on Luzon (philippinus), Dec to early May in Peninsular Malaysia and Jan–Jun in Indochina (nominate), late Apr and May in Kashmir and Nepal (intermedius), Nov–Apr but chiefly Jan–Mar in Assam and Bangladesh (levaillantii), Mar–Apr in N India, and Apr–Sept but chiefly May–Jul in Sri Lanka (culminatus). Has long-term pair-bond. Solitary breeder. Nest built by both sexes, a platform of twigs and sticks, with deep cup lined with soft materials such as wool and hair, placed c. 7–10 m above ground in prominent tree fork, sometimes in crown of palm. Clutch 3–6 eggs (mean 4); incubation almost entirely by female, period 17–19 days (mean 18 days); chicks fed by both parents, leave nest at 3 or 4 weeks; family-members roost close to nest for c. 19 days after fledging, do not return to site once they have joined communal roost, but continue to keep together for up to 94 days after fledging. Nests parasitized by Common Koel (Eudynamys scolopaceus).

Not globally threatened. Widespread and quite numerous over most of its range. Few reports from Borneo, where rare; several specimens collected there in the past. Statements concerning its presence in NE Iran and extreme S Turkmenistan, and in Tajikistan and adjacent parts of N Afghanistan, almost certainly erroneous, as habitats there unsuitable (likely that such references are due to confusion with C. corone and/or C. ruficollis and C. corax). In Afghanistan it is confined to extreme E, where common in forest to N & E of Jalalabad. Over remainder of range it is a common and widespread species, which has benefited from man's forestry policies, opening up swathes and large clearings, providing open areas for foraging. In Malay Peninsula it has spread across the country with the opening-up of forests, having reached the hill stations of Cameron Highlands and Fraser's Hill in late 1940s and early 1950s, respectively; has also colonized Singapore over recent decades. As with C. splendens, evidence from India suggests that the amount of insects, particularly grasshoppers and locusts, that this corvid consumes outweighs the damage that it causes in fields of growing crops.