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FALCONID®, DIURNAL BIRDS OF PREY. 209 
somewhat of a vulturine nature; they feed much upon carrion, are rather sluggish 
in habit, and lack the spirit of the typical hawks. Details of form vary in the three 
genera Polyborus, Ibycter, and Milvago. ‘There are less than twelve species, all 
confined to America. 
3. The harriers are another small group, in which a ruff, forming an imperfect 
facial disk, as in the owls, is more or less developed. It consists of the genus 
Circus and its subdivisions (to which some add Polyboroides, of Africa), comprising 
about fifteen species of various parts of the world. Our species is a typical example. 
4.. The jish-hawks, of the single genus Pandion, with four or five species or races 
of various parts of the world, are remarkably distinguished from other birds of the 
family by the lack of aftershafts, a special tract-formation, a peculiar conformation 
of the feet, and other characters as noticed further on. 
5. The genus Pernis is distinguished from ordinary Falconide, in having the 
whole head softly and densely feathered. P. apivorus, the bee-eating hawk of 
Europe, is the type. It approaches the kites. 
6. The kites form a rather extensive group of hawks averaging undersized 
and of no great strength, though very active, generally of lithe and graceful shape, 
with long pointed wings and often forked tail. They subsist on small game, 
especially insects, which they capture with great address. The eye is commonly 
unshielded. Besides the genera given beyond, there are several others: Milvus, 
near which our Nauclerus stands, of Europe and Asia; the Indian and East Indian 
Baza, the African Aviceda, and the remarkable Machaerhamphus of Africa and 
Malacca; with the American Cymindis, and Gampsonyx. There are some thirty 
species of the group as thus constituted; but some of the genera are questionably 
enumerated here. Milvus, Nauclerus, Elanus and Ictinia are true kites. 
7. The buzzards form a large group, not easily defined, however, unless it be by 
exclusion of the peculiarities of the others. They are hawks of -medium and 
rather large size, heavy-bodied, of strong but rather measured flight, inferior in 
spirit to the true hawks and falcons, and as a rule feed upon humble game, which 
they rather snatch stealthily than capture in open piracy. The extensive genus 
Buteo with its subdivisions, and its companion Archibuteo, typify the buzzards ; 
they include, however, a variety of forms, shading into other groups. With them 
must be associated the eagles; for the popular estimate of these famous great*birds 
as something remarkably different from ordinary hawks is not confirmed by exam- 
ination of their structure, which is essentially the same as that of the buzzards, into 
which they grade. Although usually of large size, and powerful physique, they are 
far below the smallest falcons in raptorial character, prey like the buzzards, and 
often stoop to carrion. The genus Aquila may stand as the type of an eagle; its 
several species are confined to the Old World, with one exception. Haliaétus rep- 
resents a decided modification in adaptation to maritime and piscivorous habits. 
A celebrated bird of this group is the harpy eagle of South America, Thrasiaétus 
harpyia, with immense bill and feet, and one of the most powerful birds of the 
whole family. There are several other genera in either hemisphere. 
8. The hawks proper are another extensive group, of medium sized and small 
species, which, although less powerfully organized, are little, if any, inferior in spirit 
and relative strength to the true falcons. Their flight is swift, they capture their 
prey in active chase like hounds, and always kill for themselves. The wings are 
rather short, as a rule, with the tip formed by the 3d—5th quills, the 2d and Ist being 
shortened ; the tail is generally lengthened. The eye is shaded by a bony brow. 
KEY TO N. A. BIRDS. 27 
