34 FIRST LESSONS IN ZOOLOGY 



their young after birth ; indeed many of the lower ones 

 die before the young are hatched, and those that do not 

 may have gone a long distance away before that time. 

 But among the higher vertebrates, the birds and mam- 

 mals, and among a few particularly interesting inver- 

 tebrates, as the social insects and others, the parents 

 give much care and protection to their young, building 

 homes for them, providing them with food, and teaching 

 them to help themselves. Almost all animal homes 

 are built primarily for the protection and housing of 

 the young, although the parents, may, and during the 

 rearing of the young naturally do, largely live in them 

 themselves. As an example of an animal home, we may 

 observe the construction of a bird's nest, together with the 

 egg-laying and incubation and the care of the fledglings. 



A Bird's nest. — In spring and early summer, the 

 nesting-times, find close to the schoolroom a pair of birds 

 that have begun a nest. By keeping sharp watch in 

 trees and bushes they will surely be found, though most 

 birds hide their nests as effectively as possible. Robins 

 are especially good birds to watch, because they are 

 not easily frightened from their work, because they 

 build a large nest, and because they gather their nesting 

 materials mostly in the near vicinity of the nest. Be- 

 cause the robin's nest is in a tree, it may not be so eas.y 

 to watch as the nest of some bird that builds in hedges or 

 bushes. Find a robin or other bird carrying a straw in 

 its bill and trace it "home." 



In observing the nest-building, egg-laying, and incu- 

 bation try to answer the following questions : Do both 

 birds take active part in building, or but one, and if one, 

 which one, the male (jr female, and what does the other 

 do' What materials are used.? Is the nest composed 

 chielly of one kind of material, or nearl)' ecjually of sev- 

 ral .? What " tools " of the bird are used in buildinsj .' 



