FALCON1. HA WXS, ETC. 281 



ORDER X, FALCONI. HAWKS, ETC. 



Sternum, stout and arched. Keel, high. Furcula, very strong and considerably arched. 

 Head, not large. 



Although some of the members of this Order resemble the Owls somewhat in external 

 forms, I hey dill'er widely from them in many internal characters. The eyes in both orders 

 are quite large but among the present birds, they are not directed quite so well forward, 

 neither are they especially adapted for seeing by night. The bill, as in the Owls, is strong 

 and curved but is not often concealed by bristly feather?. Usually there is no disk of 

 feathers surrounding the face but this is occasionally present, notably among the species 

 in Circus, in which genus the cavity of the ear is also large; yet this is not so remarkable 

 in other Hawks. The tarsus is usually rather long and naked but is occasionally feath- 

 ered, even to (he toes. The wings arc long and well formed but the plumage is compact, 

 especially that by which flight is produced. The sternum is always strong, with either an 

 unbroken margin or two or four marginal indentations. These are oftener closed than open 

 but they diller widely in this respect, as will be seen under family and generic characters. 

 The keel is quite high as a rule, although it does not always equal in height one half the 

 width of the sternum and seldom exceeds it. The costal process is much smaller than in 

 the preceding order. The coracoids are stout and of medium length, as in the Owls, and 

 an 1 set on at a. wide angle hut, unlike the latter named order, where the furcula is notice- 

 ably weak and without a terminal expansion, in these birds, it is very strong, well arched, 

 and has a slight terminal expansion. The scapula is similar in form to that of the OwJs 

 but is mere inclined backward toward the sternum than in the latter named order, where 

 it is set on at nearly a right angle with the coracoid. The manubrium is usually present 

 but small. All this sternal structure indicates that its possessors are not only endowed 

 with powerful flight but that they are capable of making very rapid and abrupt aerial 

 evolutions. 



As in the Owls, the oesophagus is wide but in these birds, it is dilated into a crop of 

 considerable size. The proventriculus is very well developed. The stomach is large but 

 not muscular. Although the fold of the duodenum is quite long, the pancreas is not very 

 largo. There are two coeca but they are not very well developed, often, in fact, being 

 rudimentary. The females are larger than the males. 







FAMILY i. MILVIDA:. THE KITES. 



The sternum, about equals in width the length of the coracoids and the scapular process of 

 the latter does not meet the furcula. Marginal indentations, two, inclosed. 



In this family, I have included a number of genera which, although they vary greatly 

 in external form, agree in sternal characters as given above. The manubrium is moder- 

 ately well developed but is not forked. The farcula is stout, flattened by lateral expansion, 

 wide and thick near the base which is abruptly truncated, not being produced into a point. 

 The terminal expansion is small and the furcula near it is contracted, furrowed above, 



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