GONADAL HORMONES AND SOCIAL BEHAVIOR 



1253 



Fig. 20.6. Summary 

 (Petersen, 1955). 



Unpaired birds, proba])ly males, selected 

 burrowing sites and set up limited territory. 

 Pairing resulted from the persistent return- 

 ing by the female to an area in the face of 

 aggressive attack. After the pair-bond was 

 formed, both mates shared in the attack 

 on trespassers. After the reproductive cycle 

 was comjileted, and after the end of nest- 



ing, toleration of other individuals was re- 

 stored and flocking ensued. Peterson related 

 the sequence of social, sexual, and ])arental 

 behavior patterns (Fig. 20.5) to physiologic 

 and morphologic changes (Fig. 20.6). 



Modifications in agonistic behavior occur 

 in continuous breeders and under the nonsea- 

 sonal conditions of the laboratory. The non- 



