CROW (Dutch, kraai, Ger. Krähe, Fr. corbeau, Lat. corvus), a name most commonly applied in Britain to the bird properly called a rook (Corvus frugilegus), but perhaps originally peculiar to its congener, nowadays usually distinguished as the black or carrion-crow (C. corone). By ornithologists it is also used in a far wider sense, as under the title crows, or Corvidae, is included a vast number of birds from almost all parts of the world, and this family is probably the most highly developed of the whole class Aves. Leaving out of account the best known of these, as the raven, rook, daw, pie and jay, with their immediate allies, our attention will here be confined to the crows in general; and then the species of the family to which the appellation is more strictly applicable may be briefly considered. All authorities admit that the family is very extensive, and is capable of being parted into several groups, but scarcely any two agree. Especially must reserve be exercised as regards the group Streperinae, or piping crows, belonging to the Australian Region, and referred by some writers to the shrikes (Laniidae): and the jays too have been erected into a distinct family (Garrulidae), though it seems hardly possible to separate them even as a subfamily from the pies (Pica and its neighbours), which lead almost insensibly to the typical crows (Corvinae). Dismissing these subjects for the present, it will perhaps be most convenient to treat of the two groups which are represented by the genera Pyrrhocorax or choughs, and Corvus or true crows in the most limited sense.
Pyrrhocorax comprehends at least two very good species, which have been needlessly divided generically. The best known of them is the Cornish chough (P. graculus), formerly a denizen of the precipitous cliffs of the south coast of England, of Wales, of the west and north coasts of Ireland, and some of the Hebrides, but now greatly reduced in numbers, and only found in such places as are most free from the intrusion of man or of daws (Corvus monedula), which last seem to be gradually dispossessing it of its sea-girt strongholds, and its present scarcity is probably in the main due to its persecution by its kindred. In Britain, indeed, it would appear to be only one of the survivors of a more ancient fauna, for in other countries where it is found it has been driven inland, and inhabits the higher mountains of Europe and North Africa. In the Himalayas a larger form occurs, which has been specifically distinguished (P. himalayanus), but whether justifiably so may be doubted. The general colour is a glossy black, and it has the bill and legs bright red. The remaining species (P. alpinus) is altogether a mountaineer, and does not affect a sea-shore life. Otherwise it frequents much the same kind of localities, but it does not occur in Britain. The alpine chough is somewhat smaller than its congener, and is easily distinguished by its shorter and bright yellow bill. Remains of both have been found in French caverns the deposits in which were formed during the “Reindeer Age.” Commonly placed by systematists next to Pyrrhocorax is the Australian genus Corcorax, represented by a single species (C. melanorhamphus), but this assignment of the bird, which is chiefly a frequenter of woodlands, cannot be admitted without hesitation.
Coming now to what may be literally considered crows, our attention is mainly directed to the black or carrion-crow (Corvus corone) and the grey, hooded or Royston crow (C. cornix). Both these inhabit Europe, but their range and the time of their appearance are very different. The former is, speaking generally, a summer visitant to the south-western part of Europe, and the latter occupies the north-eastern portion—an irregular line drawn diagonally from about the Firth of Clyde to the head of the Adriatic roughly marking their respective distribution. But both are essentially migrants, and hence it follows that when the black crow, as summer comes to an end, retires southward, the grey crow moves downward, and in many districts replaces it during winter. Further than this, it has been incontestably proved that along or near the boundary where these two birds march they not infrequently interbreed, and it is believed that the hybrids, which sometimes wholly resemble one or other of the parents and at other times assume an intermediate plumage, pair indiscriminately among themselves or with the pure stock. Hence it has seemed to many ornithologists who have studied the subject, that these two birds, so long unhesitatingly regarded as distinct species, are only local races of one and the same dimorphic species. No structural difference—or indeed any difference except that of range (already spoken of) and colour—can be detected, and the problem they offer is one of which the solution is exceedingly interesting if not important to zoologists in general. Almost omnivorous in their diet, there is little edible that comes amiss to them, and, except in South America, they are mostly omnipresent. The fish-crow of North America (C. ossifragus) demands a few words, since it betrays a taste for maritime habits beyond that of other species, but the crows of Europe are not averse on occasion to prey cast up by the waters. The house-crow of India (C. splendens) is not very nearly allied to its European namesakes, from which it can be readily distinguished by its smaller size and the lustrous tints of its darkest feathers, while its confidence in the human race has been so long encouraged by its intercourse with an unarmed and inoffensive population that it becomes a plague to the European abiding or travelling where it is abundant. Hardly a station or camp in British India is free from a crowd of feathered followers of this species, ready to dispute with the kites and the cooks the very meat at the fire. (A. N.)
- As bearing upon this question may be mentioned the fact that the crow of Australia (C. australis) is divisible into two forms or races, one having the irides white, the other of a dark colour. It is stated that they keep apart and do not intermix.