BIRDS 



75 



and kingfisher (Fig. 58) catch and eat fish for food, yet a glance at 

 the two figures shows how unlike in form these two birds are. 



A second scheme of classification is that based upon their habitat. 

 Thus we may speak of water birds, shore birds, marsh birds, and land 

 birds. This plan, too, may group together birds strikingly unrelated 

 in structure and habits, as becomes clear when we compare two 

 land birds like the hawk (Fig. 64), and the sparrow (Fig. 70). 



57. Scientific classification of birds. Modern scientific classi- 

 fication divides the birds of North America into seventeen groups or 



FIG. 60. Blue heron. (Wright's " Citizen Bird.") 



orders, all the birds of a given order resembling each other more or 

 less in structure. The common names given to some of these orders 

 are suggested by their habits. As examples we may name diving 

 birds (loon), long-winged swimmers (gulls and terns), scratching 

 birds (hens, turkeys, and quails), birds of prey (eagles, hawks, and 

 owls), and woodpeckers (downy woodpecker). The highest order, 

 known as the perching birds, is divided into twenty families, some of 

 which are the crow family, the sparrow family, the warbler, and the 



