Falco Lagopus, Gmel.
PLATE CLXVI. Male.

Should the bird known in Europe by the above name, and that found in the United States, prove to be identical, I should not be a little surprised, as I consider our Rough-legged Falcon and the Falco niger of Wilson to be of the same species, the difference in their colour being merely indicative of a difference in age.

While at Boston, in the winter of 1832, I offered premiums for birds of this family, and received as many as eight at one time, of which not one resembled another in the colour of the plumage, although they were precisely similar in form and internal structure. The females were similar to the males, but were distinguished by their superior size. These eight birds, and some others which I examined, were all shot on the same salt marshes, within about five miles of the city. Their flight was precisely similar, as were their usual attitudes, either when perched on the branches of trees, stakes, or stalks of salt grass-hay, or when alighted on the banks of the ditches to watch for their prey. The darker the bird the more shy it was; when pursued it would fly at a much greater elevation and farther off than the light coloured individuals; and I feel confident, from my knowledge of birds, that this difference as to shyness arose from the circumstance, that the dark birds were the oldest. When listening to their disagreeable squealing notes, I could perceive no difference whatever. All these Hawks arrived in the marshes within a day or two of each other, in straggling parties of four or five, and the individuals composing these parties remained near each other as if retaining a mutual attachment. These and similar observations, made in other places from the Bay of Fundy to the marshes and meadows in the maritime districts of the State of Maryland, have convinced me that these Hawks form only one species.

The Rough-legged Hawk seldom goes farther south along our Atlantic coast than the Eastern portions of North Carolina, nor have I ever seen it to the west of the Alleghanies. It is a sluggish bird, and confines itself to the meadows and low grounds bordering the rivers and salt-marshes, along our bays and inlets. In such places you may see it perched on a stake, where it remains for hours at a time, unless some wounded bird comes in sight, when it sails after it, and secures it without manifesting much swiftness of flight. It feeds principally on moles, mice, and other small quadrupeds, and never attacks a duck on the wing, although now and then it pursues a wounded one. When not alarmed, it usually flies low and sedately, and does not exhibit any of the courage and vigour so conspicuous in most other hawks, suffering thousands of birds to pass without pursuing them. The greatest feat I have seen them perform was scrambling at the edge of the water, to secure a lethargic frog.

They alight on trees to roost, but appear so hungry or indolent at all times, that they seldom retire to rest until after dusk. Their large eyes indeed, seem to indicate their possession of the faculty of seeing at that late hour. I have frequently put up one, that seemed watching for food at the edge of a ditch, long after sunset. Whenever an opportunity offers, they eat to excess, and, like the Turkey Buzzards and Carrion Crows, disgorge their food, to enable them to fly off. The species is more nocturnal in its habits than any other Hawk found in the United States.

Nothing is known respecting their propagation in the United States, and as I have no desire to compile, I must pass over this subject. They leave us in the beginning of March, and betake themselves to more northern countries; yet not one did either myself, or my youthful and enterprising party, observe on my late rambles in Labrador.

I have given you the figure of what I suppose to have been a middle-aged bird, and will at another time place before you one of the dark-coloured kind, known by the name of Falco niger, but which I consider as the old bird of the present species.

However highly I esteem the labours of Wilson, I am here compelled to differ from him. How that accurate observer made two different species of the young and the adult Rough-legged Falcon, I cannot well understand, more especially as his description of Falco lagopus and F. niger are so similar, that one might infer from their comparison that they referred to the same species.

Of Falco lagopus he says:—"The Rough-legged Hawk measures twenty-two inches in length, and four feet two inches in extent; cere, sides of the mouth, and feet, rich yellow; legs feathered to the toes, with brownish-yellow plumage, streaked with brown; femorals the same; toes comparatively short; claws and bill blue-black; iris of the eye bright amber; upper part of the head pale ochre, streaked with brown; back and wings chocolate, each feather edged with bright ferruginous; first four primaries nearly black about the tips, edged externally with silvery in some lights; rest of the quills dark chocolate; lower, side, and interior vanes white; tail-coverts white; tail rounded, white, with a broad band of dark brown near the end, and tipt with white; body below, and breast, light yellow ochre, blotched and streaked with chocolate. What constitutes a characteristic mark of this bird, is a belt or girdle of very dark brown, passing round the belly just below the breast, and reaching under the wings to the rump; head very broad, and bill uncommonly small, suited to the humility of its prey.

"The female is much darker both above and below, particularly in the belt or girdle, which is nearly black; the tail-coverts are also spotted with chocolate; she is also something larger.

"The Black Hawk is twenty-one inches long, and four feet two inches in extent; bill bluish-black; cere and sides of the mouth orange-yellow; feet the same; eye very large; iris bright hazel; cartilage overhanging the eye prominently, of a dull greenish colour; general colour above brown-black, slightly dashed with dirty white; nape of the neck pure white under the surface; front white; whole lower parts black, with slight tinges of brown; and a few circular touches of the same on the femorals; legs feathered to the toes, and black, touched with brownish; the wings reach rather beyond the tip of the tail; the five first primaries are white on their inner vanes; tail rounded at the end, deep black, crossed with five narrow bands of pure white, and broadly tipped with dull white; vent black, spotted with white; inside vanes of the primaries snowy; claws black, strong, and sharp; toes remarkably short."

I have frequently examined the very specimen from which Wilson took his figure of the Falco niger, and which is now in the collection of the Academy of Natural Sciences at Philadelphia. On comparing it with specimens of the Rough-legged Falcon in its ordinary states, I could discover no essential differences, nor, in fact, any excepting such as have reference to colour, a circumstance or quality which in hawks is known to vary so much in almost every species at different periods of their lives, that it would be useless for me to offer any remarks on the subject. Besides this, Wilson's figure is by no means correct as to colouring, it being in fact black, in contradiction to his description. I have beside me specimens in which the colour of the plumage is very different, some being quite light, others almost black; and I feel pretty confident that further researches respecting this species will shew that my opinion is not incorrect, when I say that the Rough-legged Falcon of America and the Falco niger of Wilson, are the same bird.

I am of opinion that the reason for which the dark coloured individuals are of much rarer occurrence with us, than the lighter ones, is, that the former being older and stronger birds, are much better able to bear the inclemency of the weather in more northern regions.

Middle aged Male. Plate CLXVI.

Bill short, as broad as deep at the base, which is cerate, the sides convex; upper mandible with the dorsal outline straight and declinate at the base, soon becoming convex, the tip trigonal, descending obliquely, acute, the sharp margin undulated and perpendicular; lower mandible with the back convex, the edges sharp, arched, and inflected, the tip obliquely truncate. Nostrils large, subovate in the fore and under part of the cere. Head rather large, broad, neck of moderate length, body robust. Feet short, robust; tarsi roundish, feathered; toes short, and rather small, hind toe and inner strongest and nearly equal, the latter connected with the middle at the base by a short membrane, the outer smallest; all with four transverse scutella at the end, the rest of their upper parts covered with very small hexagonal scales; claws compressed, strong, curved, acute, flat beneath.

Plumage ordinary, soft beneath. Space between the bill and eye covered with bristly feathers, the bases of which are furnished with short barbs. Feathers of the head and neck lanceolate, of the back and breast broad and rounded, of the legs short and narrow, excepting the external tibial, which are long and rounded. Wings long, third quill longest, fourth almost equal, second shorter than fifth, first very short; first four abruptly cut out towards the end on the inner web; secondaries broad and rounded. Tail rather long, broad, rounded.

Bill dull bluish-grey, black at the end. Iris hazel, projecting part of the eye-brow greenish-blue, cere yellow. Toes yellow, claws black. Bases of the black bristles of the lore whitish. The head and neck are streaked with umber-brown and yellowish-white, the centre and tip of each feather being of the former colour. Back umber-brown, variegated with light reddish-brown and yellowish-white. Quills dark brown towards the end, the outer webs of the first six tinged with grey, the base of all white, that colour extending farther on the secondaries, of most of which, and of some of the primaries, the inner web is irregularly barred with brown. Upper tail-coverts white, irregularly barred with dark brown. Tail white at the base, brown and mottled towards the end, with a broad subterminal bar of brownish-black, the tips brownish-white. Middle and hind part of the thorax, with the sides blackish-brown. Breast yellowish-white, largely spotted and blotched with umber. Feathers of the legs paler yellowish-red, barred with dusky; abdomen yellowish-white, as are the under tail-coverts, which are marked with a small brown spot.

Length 22 inches, extent of wings 4 feet 1 inch; bill along the back 1?, along the edge 1 7/12; tarsus 2 11/12.

The Female agrees in colouring, but is considerably larger.

The old bird, which has a very different look as to colour, has been noticed or described under different names.

The bill, feet, and iris, are coloured as in middle age; but the plumage is of a nearly uniform chocolate-brown, the bases of the quills, however, remaining white, the broad band on the under surface of the wing being the same as in the younger bird; and the tail being brown, without a subterminal bar of black, but slightly tipped with brownish-white, and barred with yellowish-white on the inner webs, the bars becoming more distinct on the outer feathers. The wings in both reach to near the tip of the tail. The feathers on the nape of the neck are white excepting at the extremities, which is also the case in the young and middle aged birds, and is not a circumstance peculiar to this species, being observed in F. Albicilla, F. palumbarius, F. Nisus, and many others.