430 ZOOLOGY 



likely to meet, are: the crow family (Corvida; Fig. 226) including 

 crows, and blue jays; the sparrows and finches (FringillidcB), 

 including also snow birds, crossbills, and grosbeaks; the oriole 

 family (Icterida) including orioles, bobolinks, meadowlark, and 

 the blackbirds; the warblers (Mniotiltida) , small migrating 

 birds with bright colors and most interesting and attractive 

 qualities; the wrens (Troglodytida) ; and, finest of all, the thrush 

 family (Turdidoz), including the various thrushes, the robin, 

 bluebirds, and many others. 



For further description of the numerous interesting families 

 of Passeres the student must refer to some special book on 

 birds. The study of their habits and form constitutes one of 

 the most popular and entertaining subjects of natural history 

 for the recreation studies of busy people. Much good, and 

 some very indifferent, literature intended for guidance in such 

 studies is now being produced. 



442. Relation to Nature. It is easy to be seen from the fore- 

 going discussion that birds, while very much alike in funda- 

 mental structure, have succeeded in adjusting themselves to a 

 remarkably varied life. In structure this adaptation is shown 

 in the size and shape of the body, in the modifications of such 

 external structures as neck, beak, legs, toes, claws, wings, and 

 tail. Among the instincts and habits the following have a large 

 place in the adaptations of birds: the food habits, instincts of 

 song, nesting and breeding instincts, care of young, and response 

 to climatic changes as shown in the migration impulses. 



Wings vary from the most rudimentary remnants, as in the 

 ostrich and apteryx (kiwi), to the powerful ones of ducks which 

 drive the birds at a rate of ninety miles an hour. The tail is 

 equally variable. There may be no special tail feathers, as in 

 the kiwi, or the tail may be of the most striking character, as 

 in the male peafowl or bird of paradise. In these extreme styles, 

 as in many birds of smaller size, the tail is a sex development, 

 the male usually having greater specialization. Tails of more 

 normal size serve as balancers when the birds are perched and 

 as rudders when they fly. 



The legs and neck are closely related in length. If the legs 



