1966 THE DIURNAL BIRDS OF PREY 



around, frequently uttering their calls, and circling in and out among the tree tops 

 so fast as to make one dizzy to look at them. Except during this season, one seldom 

 sees one of these birds unless it is flying, and I have often wondered if they did not 

 at times sleep on the wing. At least I know that they usually, if not always, eat 

 while flying; for I have many times seen one sailing leisurely along, occasionally 

 bending its head to tear a piece from a small snake that it held in its talons, and I 

 have never seen one alight on its food, as other birds of prey do. When hunting, 

 they fly close to the ground, like marsh harriers, but at other times they sail above 

 the tree tops, and sometimes so far above that it takes a good eye to see them. 

 Their food consists almost entirely of reptiles; small snakes seem to be a favorite 

 article of food with them. I have never seen one catch a bird, and believe they do 

 not. This habit of eating snakes has given them the name of snake hawk among 

 the natives of Florida." These birds begin to arrive from the south in the latter 

 state about the middle of March, but do not become common till two or three weeks 

 later. There they nest in April, usually building in tall pines, frequently at a 

 height of ninety, and sometimes as much as a hundred and thirty feet from the 

 ground. The nest is a very irregular structure of mossy twigs, and usually con- 

 tains two eggs, spotted and blotched with rich brown and ferruginous. The African 

 swallow-tailed kite (Nauclerus riocouri) is about two-thirds the size of the above, 

 with relatively shorter wings. It is grayish above and white beneath, and is con- 

 fined to the western and northeastern parts of the continent. 



The vulturine sea eagle (Gypohierax angolensis) brings us to a 



group of four genera which, while agreeing with the preceding in the 



shortness of the bare portion of the metatarsus, differ in the absence 



of a flap of membrane to the nostrils, which have a clean, bony margin. In three 



of them the aperture of the nostril is oval, with its longer axis placed more or less 



nearly at right angles to that of the beak, but in Haliastur the aperture is circular. 



In all, the tails are rounded or slightly emarginate. It may be well to mention 



that Haliastur is represented by the common brahmany or maroon-backed kite (H. 



indus], easily recognized by its white head, neck, throat, and breast, and the 



maroon chestnut of the rest of the plumage. 



The vulturine sea eagle, which is the sole representative of its genus, differs 

 from the other forms with oval nostrils by the naked space above the eye, and is 

 conspicuous for its parti-colored plumage. It has a peculiarly vulture-like appear- 

 ance, and may be compared in size to the kite, the total length of the male being 

 twenty -three inches, while the female is one and one-half inches longer. The beak 

 and head are elongated and the wings very long and pointed, while the short tail is 

 very markedly rounded. In the adult bird the color of the plumage, with the 

 exception of the ends of the primary quills, the secondaries, most of the scapulars, 

 and the tail feathers (save their tips), which are black, is pure white. The cere is 

 gray, the bare skin of the face flesh colored, the iris light yellow, and the foot rosy 

 flesh colored. The feathers of the hinder part of the head are somewhat elongated, 

 so as to form a slight crest. In the young the whole plumage is dark brown and 

 the iris also brown, the complete change to the adult dress not taking place till the 

 third or fourth year. This bird is exclusively African, and is met with on the west 



