The above detailed account appears to me to furnish a better description of the adult Jer Falcon than any that I have met with, and cannot fail to be acceptable to ornithologists.
On inquiring of a Mr Jones, who had been a resident in Labrador for twenty years, I was informed that these Hawks feed on and destroy an immense number of hares, Rock Partridges, and Willow Grous; but he could not give me any information as to the change of plumage, never having seen them in any other state than that of the individuals represented in my plate, which I shewed to him. The fishermen called them Duck Hawks, and some of them reported many exploits performed by them, which I think it unnecessary to repeat, as I considered them exaggerated.
Falco Islandicus, Lath. Ind. Ornith. p. 32. Adult—F. rusticolus, Idem, p. 28. Adult—F. Gyrfalco, Idem, p. 32. Young.—F. sacer, F. obscurus, and F. lagopus β, Idem.—Temminck, Manuel, part i. p. 17.—Swains. and Richards. Fauna Bor.-Amer. vol. ii. p. 27.
Gyrfalcon, Falco islandicus, Nuttall, Manual, part i. p. 51.
Male in immature state. Plate CXCVI. Fig. 1.
Bill shortish, as broad as deep at the base, the sides convex, the dorsal outline curved from the base; upper mandible cerate, the edges a little inflected, rather obtuse, nearly straight to the tooth-like process, which is rather rounded, the tip trigonal, descending, acute; lower mandible involute at the edges, truncate at the end, with a notch near it on either side, corresponding to the process above. In an individual which I have seen, the margin line of the upper mandible was undulated, or formed a festoon behind the tooth, but in my two specimens, the skin of one of which is now before me, it is quite straight when viewed directly, although when placed obliquely it shews a slight undulation. Nostrils round, basal, lateral, with a soft papilla in the centre, connected with the upper edge. Head rather large and round; neck shortish; body ovate, anteriorly broad; the whole conformation indicative of great strength and activity, such as befit a hunter. Legs robust, short; tarsus feathered more than half way down, their exposed part covered anteriorly with small quincuncial transversely oblong scales, as is the proximal portion of all the toes, posteriorly with smaller papillar scales (there are no broad scales or other scutella on the tarsus, as in most other Hawks, and in the Peregrine). Toes, excepting at the base, covered above with broad scales or scutella, scabrous and tubercular below; middle and outer toes connected by a membrane; second and fourth toes nearly equal, the latter very little longer, the hind toe shortest, but with the longest claw; claws strong, curved, acute, marginate beneath, convex above.
Plumage compact, imbricated. Feathers of the head short and narrow, of the back rounded, of the neck and breast broadly oblong, of the thighs long and rounded. Space between the bill and eye covered with short bristly feathers. Wings long, about four inches shorter than the tail; the third quill longest, but scarcely longer than the second, the first and fourth of the same length. The first and second are cut out or sinuated on the inner edge towards the tip, the second slightly. The tail is long, straight, slightly rounded, of twelve broad feathers, which at the end suddenly taper to a point. When worn, they seem rounded, but in my specimens the plumage was new.
Bill and cere pale blue, the rather narrow ridge of the upper mandible darker. Iris brownish-black. Feet greyish-blue, the under parts of the toes greenish-yellow; claws dusky. The general colour of the plumage above, is brownish-grey, the feathers having a very narrow margin of paler. Some of the upper tail-coverts are tipped with brownish-white, and the base or concealed part of the posterior cervical feathers is of that colour. The quills are more or less mottled with brownish-white on the inner webs. The tail is transversely barred with thirteen rows of transversely oblong spots of brownish-white, confined chiefly to the inner webs, although there are some on the outer ones towards their end; the tips are of the same light colour. A few of these spots appear on the upper surface of the feathers towards their extremities. The tail is moreover very obscurely barred with darker. The two middle feathers are without white spots. The throat is brownish-white, finely streaked with brown. The lower parts in general are brownish-white, longitudinally patched with dark brown, the central part of each feather being of the latter colour. The under wing-coverts are similarly marked, as are the under tail-coverts, which are alternately barred with brown and white.
Length 22½ inches, extent of wings 4 feet 1 inch; bill 1 4⁄12 along the ridge, 1½ along the edge; tarsus 2.
The Female in the same state. Plate CXCVI. Fig. 2.