Adult Male. Plate CLXXIII. Fig. 1.
Bill very short, feeble, much depressed and very broad at the base, compressed towards the tip, upper mandible with the ridge straight and sloping, the sides towards the end convex, the edges sharp and overlapping, having a slight notch close upon the tip, which is very small, rather obtuse, and declinate; lower mandible flattish, the edges inflected, the tip acute. Nostrils basal, lateral, oblong, with a membrane above. Head of ordinary size, neck short, body rather slender. Feet very small and feeble, tarsus very short, anteriorly scutellate, sharp behind; toes free, lateral nearly equal, the outer united as far as the second joint; claws shortish, arched, much compressed, very acute.
Plumage rather compact and shining above, blended and with ordinary lustre beneath. Wings very long and narrow, primaries narrow and tapering to a rounded point, the first longest, the rest gradually diminishing; secondaries very short, truncato-emarginate.
Bill black. Iris hazel. Feet purplish-black. Anterior part of the forehead bright chestnut; the rest of the head, the hind neck, back, rump and smaller wing-coverts glossy deep steel-blue. Quills and tail brownish-black, the latter with a white spot on the inner web of each feather, excepting the two middle ones. Throat bright chestnut; a broad band of black glossed with steel-blue on the lower part of the neck, joining the dark colour of the upper parts. The rest of the lower parts light brownish-red.
Length 7 inches, extent of wings 13; bill along the back 3⁄12, along the edge 7⁄12; tarsus 4⁄12.
Adult Female. Plate CLXXIII. Fig. 2.
The Female differs from the Male only in being generally paler beneath.
The young bird fully fledged has the red of the forehead and throat paler, the band on the forepart of the breast brownish-black, without gloss, and the rest of the lower parts white tinged with red.
There is considerable diversity in the colouring of the under parts of this bird. Frequently there is a broad band of steel-blue across the neck or fore part of the breast, in other cases this band is narrow, or interrupted in the middle, or wanting, as in the individuals represented in the plate. The rufous colour of the breast, sides and belly varies from reddish-white in young birds to bright brownish-red in old ones. In the former case it is singular to the colour of the European Chimney Swallow, which, on the other hand, never has those parts so deeply tinted as in the latter case. The bill and feet of the two are precisely similar as are the colours of the upper parts; but in the European bird, the dark band on the fore part of the breast is much broader, the first and second primaries are almost equal, although the first is longest, and the lateral tail-feathers are more elongated. These differences do not seem to me to be sufficient to distinguish the two birds as species, and the similarity of their habits renders them too nearly allied to be separated with propriety.
The differences in colour between the European Chimney Swallow and the American Barn Swallow, are analogous to those between the Barn Owl of the former and that of the latter country. The Swallows and the Owls may be distinct species; but I see no reason for separation in the one case more than in the other; and if the so called Hirundo Americana be distinguished from the H. rustica, the Strix flammea ought to be distinguished from the American Owl, which might in that case be named Strix Americana. But let the differences first be shewn.