TERRITORY 



169 



females on the nesting ground, and of adults than first-year birds; 

 selection of territory, song, fighting and display of plumage are ex- 

 plainable on the basis of the necessity of synchronizing the mating 



Fig. 35. — Map of song-sparrow territories. The letters A, B, C, represent the 

 first, second and third nestings. (After Nice, 1931.) 



cycles of male and female. In order to insure the propagation of the 

 strongest birds, the virile male must keep all other males out of his 

 territory and must drive out all females that are not in the same 

 reproductive cycle as himself, lest another male mate with his female 



