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BRANCH CHORDATA 



terial they find on the ground, while the arboreal forms more 

 often use small twigs for their nests, which they sometimes line 

 with finer material, such as strings and hairs. The woodpecker 

 uses no material but the tiny chips he has made in digging the 

 hole. The swift glues together the twigs of its nest by a sticky 

 saliva. According to the manner in which they construct their 

 nests, birds have been variously styled weavers, tailors (Fig. 

 221), carpenters, or masons, and their tools vary according to 



Fig. 220. Brown pelican and nest in young cabbage palmetto. (Photo- 

 graph by Frank M. Chapman.) (Y. B. U. S. Dept. of Agricul.) 



the work to be done, or vice versa. Sometimes both sexes build 

 the nest, or one collects the material and the other arranges it. 

 In other cases the male sits by and sings, leaving the building 

 to his mate. The position of the nest varies. It may be placed 

 upon the ground, like that of the quail, or on a rock, like the 

 penguin's, or suspended far out on the swaying branches, like 

 the delicate hanging nest of the oriole (Fig. 222). The object 

 of the position, of course, is for protection. One must observe 



