284 NATURAL HISTORY OF BIRDS. 



eagle of Australia. This latter differs from all the other members of the genus in 

 having the long tail strongly graduated, the outer feathers being five or six inches 

 shorter than the middle ones. 



Severtzoff, in his "Fauna of Turkestan," says of the king-eagle, A. heliaca, 

 "During summer it is found in all parts of Turkestan, but breeds only in the salt 

 plains near Jorteck. During the breeding-season it is only found near its breeding- 

 haunts, but frequently wanders and changes its residence during the winter. Like 

 other eagles, it breeds only every alternate year. So soon as the young are full- 

 grown they commence to change ; but the plumage changes very slowly. During the 

 winter the moult is arrested, and recommences in the spring of the following year; 

 and they never breed whilst this moult is progressing." 



Among the sea-eagles, the North American bald-eagle, Ilallaetus leucocephalus, is 

 a familiar example, and too well known to need description. Of about the same size 

 as the golden-eagle, it differs much from it in habits, haunting the shores of lakes and 

 rivers, but especially the sea-shore, living mainly on fish, which it sometimes catches 

 for itself, sometimes robs the osprey of, and probably most often finds cast up dead 

 on the shore. The nest is most frequently placed on a high tree, but in sections 

 where suitable trees are not to be found, it places its nest on rocky cliffs or precipitous 

 banks. The eggs, which are laid very early in the season, are never (normally) less 

 than two, which is the regular number, though sometimes three or four are laid. 



^j d? 



They are nearly spherical, dull white, unspotted, and average about three inches by 

 two and three-quarters. 



The finest bird of the genus is undoubtedly the northern sea-eagle, Haliaetus 

 pelagicus, of northeastern Asia. It is readily recognized by its large size, with 

 extremely large bill, cuneate or graduated tail (of fourteen feathers), and white 

 thighs, shoulders, rump, and tail, the other parts being brown. The African sea- 

 eagle, II. vocifer^ is remarkable for a coloring unusual in this group. The head, neck, 

 breast, and tail are pure white, the remainder of the under parts, including the 

 thighs, sides of body, and under wing-coverts, deep chestnut ; while the upper parts 

 are brown or black. It is a comparatively small bird, being little more than half the 

 size of the bald-eagle, and closely approaching in size the common red-tailed hawk, 

 Buteo borealis. This is the smallest eagle of the genus unless we except the nearly 

 related H. vociferoides of Madagascar, which is of the same size and with somewhat 

 similar colors. Like the other members of the genus, these birds feed largely on fish, 

 and are seldom found at any great distance from water. 



Closely allied to Halia'etus, if indeed it is not really congeneric, is the peculiar 

 fishing-eagle, Polioaetus ichthyaetus, of India and the East Indies generally, an eagle 

 with almost the exact habits of the osprey (Pandion), subsisting entirely on fish, and 

 with its external anatomy much modified to suit its requirements, its talons being 

 much curved, very sharp, and rounded almost precisely as in that species. Two 

 species are known. 



Here may be mentioned a small group of two or three species very closely allied 

 on the one hand to Aquila, from which, however, they are distinguished by their 

 longer legs, and on the other to the hawk-eagles, Spizaetus and allies. The most 

 familiar member of the group in Europe is Bonelli's eagle, Nlsaetus fasciatus, a 

 common bird of the Mediterranean region, and extending eastward to India. 



Under the name of hawk-eagles are grouped a dozen or more raptors of medium 

 or large size, and often of striking plumage, belonging to several genera, mainly 



