Falco Chrysaëtos and F. fulvus, Linn. Syst. Nat. vol. i. p. 125.—Lath. Ind. Ornith. vol. i. p. 10.
Falco fulvus, Ch. Bonaparte, Synops. of Birds of the United States, p. 25.
Aquila Chrysaëtos, Swains. and Richards. Fauna Bor.-Amer. vol. ii. p. 12.
Ring-tailed Eagle, F. fulvus, Wils. Amer. Ornith. vol. vii. p. 13. pl. 55. fig. 1. Young.
Royal or Golden Eagle, Nuttall, Manual, part. i. p. 62.
Adult Female. Plate CLXXXI.
Bill shortish, deep, compressed, strong, cerate at the base; upper mandible with the dorsal outline nearly straight and sloping at the base, from the margin of the cere to the end curved so as to form the fourth of a circle, the sides sloping and slightly convex, the edges sharp, nearly straight, with a slight convexity and a shallow sinus close to the strong subtrigonal tip, which is concave or channelled beneath; lower mandible convex on its dorsal outline, the sides convex, the edges sharp and inflected, the tip obliquely truncate. Nostrils in the fore part of the cere, lateral, oblique, oval, open, with a process at their anterior margin. Head of moderate size, neck short, body full. Legs of ordinary length; the tibia proportionally long; the tarsus short, rounded, robust, feathered to the toes, which are rather short, very strong, united at the base by a short web, marginate, covered above with series of angular scales, and towards the end with large broad scutella, of which there are four on the hind toe, three on the next, four on the middle toe, and three on the outer; the first and second toes are about equal, the hind one stronger, the middle toe longest, the outer shortest and smallest; claws long, curved, rounded, flat beneath, middle claw with a deep groove and an edge on the inner side.
Plumage compact, imbricated, glossy; feathers of the head and neck narrow and pointed, of the back and breast broader, but still pointed. Space between the bill and eye covered with small bristle-pointed feathers disposed in a radiating manner; both eyelids ciliated; a bare projecting space over the eye. Wings long; the fourth quill longest, the third almost equal, the second considerably shorter, the first short; the first, second, third, fourth, fifth, and sixth, abruptly cut out on the inner webs; the secondaries long, broad, and rounded. Tail rather long, ample, rounded, of twelve broad, rounded, and acuminate feathers.
Bill light bluish-grey at the base, black at the tip; cere and basal margins yellow. Eyebrows and margins of the eyelids light blue; iris chestnut. Toes rich yellow; claws bluish-black. Fore part of the head, cheeks, throat, and under parts, deep brown. Hind head, and posterior and lateral parts of the neck, light brownish-yellow, the shafts and concealed parts of the feathers deep brown. The back is deep brown, glossy, with purplish reflections; the wing-coverts lighter. The primary quills brownish-black, the secondaries with their coverts brown, and those next the body more or less mottled with brownish-white, excepting at the ends; the edge of the wing at the flexure pale yellowish-brown. Tail dark brown, lighter towards the base, and with a few irregular whitish markings, like fragments of transverse bands; its coverts pale brown, mottled with white at the base, and paler at the ends. The short feathers of the legs and tarsi are light yellowish-brown, each with a dark shaft; the outer elongated feathers dark brown; the lower tail-coverts light yellowish-brown. The base of the feathers on the upper parts of the body is white, on the lower pale dusky grey.
Length 3 feet 2 inches, extent of wings 7 feet; bill along the back 2¾, edge of lower mandible 2½; tarsus 4½, middle toe and claw 4½, hind claw 2¾. The extremities of the wings are 1 inch short of that of the tail.