AVES 



429 



of the student. Some species of cuckoos lay their eggs in the 

 nests of other birds, where they are hatched and fed by the host. 

 In return for this they are said often to cast the young of the 

 proper owners out of the nest. 



The chimney-swifts, whippoorwill, and the humming birds 

 are somewhat intermediate between the forms just spoken of 

 and the next order. 



The Pas seres (sparrow-like) is the greatest order of birds. 

 It has more than sixty recognized families and more than 6,000 



FIG. 232. 



FIG. 232. Loggerhead Shrikes (Lanius ludovicianus). By J. W. Folsom. 



species. About twenty to twenty-five of these families are found 

 in North America. These birds are mostly small, with three 

 toes in front and one behind, and adapted to perching. The 

 majority are gifted with some powers of song (oscines). A 

 smaller division, of which the king bird and phcebe may be taken 

 as types, are known as chattering or crying birds (clamatores) . 

 Among the families of oscines, which the student is most 



