A glance at different members of the Eagle tribe will at once convince us that they do not all belong to the same country or climate. It is true that they are dispersed over the surface of the whole earth, but each species has its appointed district; all, however, avoid the abodes of man, and make their nests in some unfrequented spot. Mountains, forests, sea-coasts, or the banks of lakes or rivers have each their appointed forms, while some species roam at large over the open plains of the countries in which they live. Such members of the family as inhabit the more northern portions of the globe migrate as winter approaches, and pass their lives in sweeping from land to land, except at such times as they are busied with the cares of incubation. In their habits all are unsocial, keeping company rarely even with individuals of their own race, except during their winter journeyings, and suffering no intruder to approach the spot selected as a breeding-place; so strong is this dislike to society that even when several Eagles are attracted by the same prey the companionship is merely in appearance, each bird coming and going without any reference to the movements of the rest. Notwithstanding this unwillingness to join company with others, even of their own species, they are much attached to their mates, each pair living in close companionship throughout their whole lives, and frequently permitting smaller birds to make their nests in close proximity, either regarding them as entirely beneath their notice, or, perhaps, feeling that such despicable morsels are not worth the long and troublesome chase which their pursuit would necessitate. To some members of the Eagle family the name of Hawk Eagles has been assigned, on account of their very decided resemblance to the Hawk, not merely in appearance, but in disposition.
Though unable to cleave the air with the rapidity of the Falcon, the flight of an Eagle is extremely imposing, as it rises with slow and majestic strokes of its large wings, steering its course by the aid of its tail, or hovers for minutes at a time without any apparent effort; when descending to seize its prey its movements are somewhat more rapid, but are not to be compared with the stoop of the Hawk. While upon the ground nothing can be more clumsy than the mode of progression employed by these large birds; they hop, or rather jump, with a most peculiar step, at the same time helping themselves along with their wings; far different is their appearance when they are seen perched with body erect upon some tree, from whence they gaze upon the world beneath with a calm dignity worthy of the royalty not unfrequently assigned to them. The sight of the Eagle is more highly developed than any other sense; it also hears well, and exhibits a marked dislike to any sharp sound. Many wonderful tales have been circulated as to the power of appreciating odours possessed by these birds, but for our own part we consider these accounts as much exaggerated. All the members of the family are intelligent, prudent, in some cases cunning, and they have such an appreciation of their own strength as to impart an air of nobility to their demeanour even towards man himself. When in pursuit, Eagles exhibit great fierceness, and seem to enjoy the full excitement of the chase; even such large quadrupeds as foxes fall victims to their ferocity, and the swiftest inhabitants of the air are not safe from their pursuit; instances are on record in which man himself has had to combat the attacks of these bold and audacious birds.
The eyries built by the various species of Eagles differ but little in appearance; all are exceedingly large, broad, and very shallow. They are formed of boughs, sometimes of considerable thickness, on these are placed smaller branches, and the interior is then padded with twigs upon which the leaves have been left, in order to form a warm bed. These nests are usually constructed upon a tree, or upon some rocky precipice. The breeding season varies according to the climate; the eggs often but one, rarely three in number, are incubated by the female alone. Both parents, however, assist in rearing their progeny, and have been known to fly to a distance of many miles in search of food for their hungry family. The nestlings are tended for some time after they are fully fledged.
Foremost among the Eagles three species stand pre-eminent, and have been celebrated and dreaded from the most ancient times. These form the group of TRUE EAGLES, and are recognisable by their powerful bodies, large and well-shaped heads, and broad long wings, which reach to the end of the tail; in the wings the fourth quill is longer than the rest; the tail is long, and the legs strong and of moderate height; the beak is large, the upper mandible curves very decidedly from the cere downwards, and bulges outwards at its sides; the eyes, which are of great size, lie partly concealed under the projecting brows; the feet are powerful and of moderate length, the claws large, curved, and sharp. The plumage is rich and soft, and its feathers pointed, those at the back of the head and on the nape being slender and elongated; the tarsi are feathered down to the toes.
Thus far we have described collectively the three species forming the family of True Eagles; but, to avoid confusion, we will now speak of the Tawny, the Golden, and the Imperial Eagles, each under its proper heading.
THE TAWNY EAGLE.
The TAWNY EAGLE (Aquila fulva), the largest, strongest, and most compactly built member of the family, is from two and three-quarters to three feet in length, and from six and two-thirds to seven feet in breadth; the wing measures from one foot two inches to two feet, and the tail thirteen or fourteen inches. The largest of these measurements applies to the female bird. When the plumage is in its full beauty, the head and back of the neck are brownish yellow, and the rest of the feathers of a uniform dark brown; the tail is white, striped, or spotted with black at its upper portion, the lower half entirely black; the hose are almost white. Naumann tells that only the two centre tail-feathers are of equal length, those towards the sides being slightly graduated.
THE GOLDEN EAGLE.
The GOLDEN EAGLE (Aquila chrysaëtos) is much more slenderly built and has a smaller head than the bird above described, but the wings and tail are longer, and the former do not extend as far as the extremity of the tail. The male is three feet long and seven feet and a quarter across the span of the wings; the wing measures two feet four inches and the tail thirteen inches; the female is three feet two inches in length, and seven feet and a half across. The plumage is lighter than that of the Tawny Eagle, and more of a reddish brown upon the breast, hose, and lower tail-covers; the region of the shoulder is indicated by a white spot; the tail is always brownish grey, marked with irregular crooked black lines, and the black stripes are narrower than in the preceding species. All the feathers that compose the tail are of equal length, except the two outer ones, which are somewhat shortened; the lower part of the wing is always very dark, and often entirely without markings. The plumage of the young is darker, and without the white patch in the shoulder, and the reddish-brown feathers on the back of the head and neck, that characterise the adult bird.