_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.[1] 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.)