Beak, tarsi, toes and claws, black. Iris brown. The general colour of the plumage is deep black, with purplish-blue reflections, the hind parts of the neck tinged with purplish-brown; the lower parts less glossy.
Length 18 inches, extent of wings 3 feet 2 inches; bill along the ridge 2 2⁄12; tarsus 2½.
The Female differs from the Male in being less glossy, but the difference is not very perceptible. The young when fully fledged are of a rather dull brownish-black, with the blue and purple reflections much less brilliant.
After a careful comparison of specimens of the European Carrion Crow with others of the American Crow, I have found decided differences, which to me seem quite sufficient to set the question of their identity at rest.
The European Crow is larger than the American; the length of the former being 20 inches, that of the latter 18; and the wing from the flexure to the extremity is proportional, being in the one 13¼ inches, in the other 12.
The bill is stronger and deeper, more convex on the sides, and with the edges more involute in the Carrion Crow than in the American Crow, the depth at the base in the former being 10⁄12, in the latter 8½⁄12.
The scutella of the tarsus in both are 10, but the feet of the Carrion Crow are much stronger and its toes and claws larger than those of the other. In the European Crow, the fourth primary is longest, the third almost equal, and this is also the case in the American, although slight differences occur in individuals.
The principal character besides the different form of the bill, is to be found in the feathers of the neck. In the European bird, the feathers of the hind neck are narrow, and although blended, have their points distinct; while in the American bird, they are broad, rounded, and perfectly blended, so that their individual form cannot be traced. The feathers of the fore neck in the former are lanceolate, compact at the end, and, although shorter, resemble those of the Raven; but in the American Crow they are three times as broad, rounded, and entirely blended.
Lastly, the American species has a decided purplish-brown tinge on the neck, while the European bird has that part glossed with green and blue.
I am happy on this occasion to have an opportunity of referring you to an excellent paper, on the specific characters of birds, by Mr Macgillivray, which you will find in the Transactions of the Wernerian Natural History Society, and in which he shews the great advantage that may be derived from attending to the structure and form of the feathers. The characters by which the American Crow is distinguished from the European Carrion Crow are an exemplification of his views, in which I cordially agree:—"Allowing," says he, "only a partial application of the principle of characterizing the species by the forms of the feathers, even this would be a matter of importance; and were the attention of ornithologists directed toward this point, there can be little doubt that discoveries would quickly be made, which would determine species and varieties with much greater precision than can be attained by attending to colour alone."