1252 



HORMONAL REGULATION OF BEHAVIOR 



a study of the annual cycle of the Cali- 

 fornia quail {Lophortyx calif ornica) . Of 

 particular interest is the shift from a peck- 

 order type of organization during sexual 

 quiescence to territoriality during the breed- 

 ing season. The establishment of breeding 

 territories by the Anna hummingbird {Ca- 

 lypte anna) has been correlated with testis 



volume and histologic changes (Williamson, 

 1956). 



An extensive study in which behavior was 

 related to the seasonal cycle was made by 

 Petersen (1955) with the migratory bank 

 swallow (Riparia riparia). These birds ar- 

 rived in the spring in flocks which congre- 

 gated at breeding sites on warm days. 



Fig. 20.5. Summary of behavior elements in the breeding cycle of tlio Ijank .swallow (Peter- 

 sen, 1955). 



