AVES 43 I 



likely to meet, are: the crow family (Corvidcs; Pig. 226) including 

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

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

 family {Icteridce) including orioles, bobolinks, meadowlark, and 

 the blackbirds; the warblers (Mniotiltidcs) , small migrating 

 birds with bright colors and most interesting and attractive 

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

 family (Turdidce), 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 entertaiiiing 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 Surroundings. — It is easy to be seen from 

 the foregoing discussion that birds, while very much alike in 

 fundamental 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 mating and of song, nesting and breeding instincts, care of 

 young, and response to climatic changes as shown in the migra- 

 tion impulses. 



Wings vary from the most rudimentary, 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 



