Having in the preceding article terminated the series of Mammiferous Quadrupeds at present existing in the Tower Menagerie, we must next direct our attention to the illustration of the Birds, a Class which, although fully entitled to the second place in the arrangement of the Animal Kingdom, is separated by a wide and almost unoccupied interval from that which unquestionably claims the foremost rank.
To commence then with the Eagles, which form a prominent group of the Rapacious Order, and are universally regarded as the most majestic, as well as the most powerful, of birds. In common with the whole Order, they are remarkable for the strong incurvation of their bill and talons, the latter of which are four in number on each of the feet, and are moved by means of a thick and strong muscular apparatus, which gives to the grasp of the larger species that extreme tenacity by which they are distinguished, enabling them to seize and carry off fish and birds, and even quadrupeds of moderate size. This innate propensity to rapine, derived from their peculiar conformation which renders them essentially flesh-eaters, indicates at once the analogical relationship borne by the Rapacious Birds to the Carnivorous Quadrupeds; and the high degree to which it is carried by the Eagles, their vast powers of flight, their towering majesty, their irresistible might, their uniform preference of living victims and rejection of the offal, render them superior to all other birds, in the same proportion as the Lion is allowed to take the lead among mammiferous quadrupeds.
The Eagles, properly so called, are characterized by a head covered with plumage and flattened above; eyes large, lateral, and deep-seated; a bill of great strength, arched and hooked at its extremity alone, and furnished at its base with a naked membrane, called the cere, in which the openings of the nostrils are situated; the wings broad and powerful; the tarsus, or that joint of each leg which is immediately above the toes, strong, short, and covered with feathers down to the very base; the toes thick and naked, three of them pointing forwards, and the fourth constantly directed backwards; and the talons of great power and strongly curved. The Golden Eagle, which occupies the right hand in the cut, is frequently three feet and a half in length from the extremity of the beak to that of the tail. His general colour is blackish brown both above and below, assuming on the legs a grayish or sometimes a reddish tinge. His beak is bluish black, covered at the base by a yellow cere; and his toes, which are also yellow, terminate in strong black talons, the posterior one of which frequently attains an enormous length. He is met with throughout the Old Continent, and more especially within the limits of the temperate zone, building his aiery, which he shares with a single female, in the clefts of the loftiest rock, or among the topmost branches of the alpine forest. From this retreat he towers aloft in search of his prey, which he pursues by sight alone, subsisting principally on other birds and on the smaller quadrupeds, which he carries off in his powerful clutch. When his hunger is extreme he sometimes pounces upon the larger animals; but in such circumstances he is compelled to content himself with sucking their blood upon the spot, and with stripping off portions of their flesh, on which to satiate his appetite at home. Instances have been known of his attaining in captivity to an age of more than a hundred years.