68 



VERTEBRATES: BIRDS. 



they sit for hours uttering their unpleasant notes, which 

 sound like cow-cow, eight or ten times repeated. They 



Fig. in. — Cuckoo. 



feed upon insects, and also eggs, which they steal from 

 the nests of other birds. 



WOODPECKERS. 

 These birds have a straight, sharp bill, with which 

 they cut into bark or wood in 

 search of insects. The tongue is 

 very long and capable of being 

 greatly extended, and is armed 

 towards the tip with barbs. By 

 means of this instrument they 

 pierce and drag forth insects 

 from their hiding-places. Twenty 

 or thirty kinds are found in North 

 America, varying in size from the 

 sparrow to that of a crow. They 

 build their nests in holes, which 

 they make witli their bills \n 

 trunks or branches of trees. 



Fig. 112.— Red-headed 



Woodpecker. 



