MATING. 65 



permanent residents of the tropics, where seasonal changes 

 are less marked, could nest at any time. Nevertheless, 

 the breeding season in the tropics is as well defined as it 

 is in more northern regions, and occurs with the return 

 of summer, or the season of rains. It is therefore at a 

 time of the year when food is most abundant. 



There is an obvious necessity for this regularity. Old 

 birds can wander over large areas in search of food, but 

 the young of many species must be fed in the nest, and 

 their food supply should be both exhaustless and con- 

 venient of access. 



Among our birds, the Hawks and Owls, .. ' .,. young 

 are fed on animal food, are the first birds to nest, while 

 those which feed their young on fruit or insects wait 

 until later in the year. 



Mating. Birds are ardent lovers. In their effort to 

 win a bride the males display their charms of song and 

 plumage to the utmost, and will even enter the lists to 

 do battle for the possession of a mate. 



It is not possible to describe here the many pecul- 

 iar customs of birds during the season of courtship. 

 It may simply be said that every bird will then re- 

 pay the closest observation. For the scientific-minded 

 there is opportunity to secure evidence bearing upon 

 the theory of Natural Selection; for every one there is 

 endless entertainment in the human traits which birds 

 exhibit. 



The Nest. The first step in nest-building is the selec- 

 tion of a site. There is almost no suitable location, from 

 a hole in the ground to branches in the tree-tops, in which 

 birds may not place their nests. Protection seems to be 

 the chief desideratum, and this is generally secured 

 through concealment. Most birds hide their nests. 

 Many sea birds, however, lay their eggs on the shores 

 or cliffs, with no attempt at concealment ; but, as a rule, 



