THE HAWK TRIBE 



J939 



differ from both in that the fourth toe is not reversible, while they resemble the 

 latter and differ from the former in their laterally- 

 directed eyes, which are never surrounded by com- 

 plete discs, and their firm plumage. In the bones 

 of the leg the tibia differs from that of the owls in 

 possessing a complete bony bridge at the lower end, 

 while in the typical forms this lower end is remark- 

 ably flattened from back to front. The canon bone, 

 or metatarsus, as shown in the accompanying figure, 

 is also longer than in the owls and ospreys, and lacks 

 the bridge at the upper end found almost universally 

 in these groups, while at its lower end the three 

 trochlese, instead of forming a very high arch when 

 seen from below (compare the figure on p. 1904), 

 are situated in nearly the same transverse plane. 

 Hence the metatarsus at once serves to distinguish 

 an owl or an osprey from an Accipitrine. In addi- 

 tion to its bridged palate, the skull of an Accipitrine 

 agrees with that of an owl in the absence of any 

 production of the lower mandible beyond its point 

 of articulation with the quadrate bone, but it differs 

 by its more elongated form. I^ike those of the owls, 

 the young have a downy coat, but the eggs, 

 although occasionally white, are very generally more 

 or less colored, usually with reddish blotches on a 

 pale ground. The whole group is carnivorous, like 

 the owls and ospreys; but, while some of its mem- 

 bers kill their own prey, others live on carrion. 



,-v, A , i j- -j i , r i- From the upper (A), front (), lower 



The Accipitrmes may be divided into four distinct (Qi and hinder (D) aspects . Cidt hinde r 

 families, namely, the falcon group (Falconidtz} , the processes of upper end; a,i>, points of 



muscular attachment ; f, foramen ; h, 



vultures (yuftunaa), secretary vultures (Serpen- facet for first toe. 



tariidcz}, and American vultures ( Cathartidce} . The 



first two of this family are closely allied; the other two differ greatly both from the 



first two and from one another. 



8 - 4 



THE LEFT CANON BONE OR MET- 

 ATARSUS OF THE BUZZARD. 



THE HAWK TRIBE 

 Family FALCONID^E 



The present family, which includes the falcons, hawks, kites, buzzards, eagles, 

 etc. , constitutes together with that of the vultures the typical Accipitrines, which 

 are collectively characterized by the following features: In the head the nostrils 

 are separated by a median partition, while on the base of the skull there are no 

 basipterygoid processes. The feathers have well-developed aftershafts, and the 



