National Geographic : 1933 Jul
EAGLES, HAWKS, AND VULTURES BALD EAGLE (Haliaeetus leucocephalus) Our national bird, the bald eagle, chosen in the early days of the Union, is figured on many of our coins, is a favored design in matters of patriotic interest, and in general is considered symbolic of our free dom. Its enormous size and the striking markings of the adult make it a promi nent species that is noted on every ap pearance. A bird of great strength and of swift and powerful flight, it is master in its haunts and has no potent enemies except man. Its life is led in the vicinity of water and only casually is it found far from that element. The food of the bald eagle is mainly fish. In Alaska severe complaint has been made that it destroys salmon during their annual runs up the streams to deposit their eggs. As the salmon cross shallow bars or cascades, leaping from pool to pool, there is no question that many are taken by eagles. Elsewhere the eagle often fishes by plunging from a height, descending at an angle on its selected prey, sometimes go ing beneath the surface. Rarely it grapples prey so large that it cannot rise with it and is under necessity of towing it to shore. This eagle also robs the osprey, being fiercely predatory in such encounters. Large birds are sometimes captured, in cluding ducks, coots, and geese. Although the eagle is sufficiently swift to seize them in flight, it ordinarily gives chase on the water, where it is able to tire them by forc ing them to dive until they become ex hausted. Although the bald eagle is said to feed on healthy birds, my own experience with it has been principally that it is constantly in pursuit of birds crippled by shooting or injured in some other way. During the hunting season I have often seen an eagle swing over rafts of ducks, which it scatters. Then, if cripples ap pear, they are pursued, and if none is sighted the eagle passes on to other hunt ing. The taking of such injured birds can hardly be condemned. These eagles have been said on occasion to kill lambs and foxes, the latter furnishing an indication of the birds' strength. In addition to living food, the bald eagle is prone to search for carrion, following regularly along shores for dead fish cast up on the beaches, and eating dead animals of other kinds as they offer. Because of this habit, many words of opprobrium have been hurled at it. There was much discussion before the bald eagle was finally adopted as our Na tion's emblem by act of Congress on June 20, 1782; Benjamin Franklin in particular favored the wild turkey. In spite of all that may be said against it, however, it must be conceded that the bald eagle is a bird of fine and noble appearance and that it is a master of the air. EAGLES GO IN FOR NEST-BUILDING ON A LARGE SCALE The nests of the bald eagle are large structures of sticks, usually placed in trees, often at a considerable height, though occa sionally on cliffs, or even directly on the ground. Nests 5 to 6 feet in diameter and the same in height are not unusual, and nests 12 feet high have been recorded. Herrick found that one near Vermilion, Ohio, was used continuously for thirty four years.* Ordinarily two eggs are laid, with occa sional sets of three or one. They are white, very rarely with slight markings of buffy brown. Where two eggs are laid, one is nearly always larger than the other. In cubation requires nearly a month, the duty being shared by both parents. The young remain in the nest for about two and a half months, and during that time the old birds are most solicitous of their welfare and safety. The young bald eagles do not attain the plumage of the adult for three years, and during the first year they are actually larger than their parents. The southern bald eagle, Haliaeetus leu cocephalus leucocephalus, nests from the northern United States to Baja Califor nia, central Mexico, and Florida. The northern bald eagle, Haliaeetusleucoceph alus alascanus, breeds from northwestern Alaska and British Columbia to the Great Lakes and Nova Scotia, coming in winter south to Washington, Montana, and Con necticut. A related species, the gray sea eagle, Haliaeetus albicilla, is resident in Green land, and is found also in Europe and northern Asia. * See "The Eagle in Action," by Francis H. Herrick, in the NATIONAL GEOGRAPHIC MAGA ZINE for May, 1929.