INFLUENCE OF THE FEMALE 111 



that took part in it had only recently arrived, 

 but the male, an unpaired bird, had been in 

 possession of its territory for some days. The 

 sequel to this struggle, which was protracted and 

 severe, was the disappearance of both females, 

 the male being left without a mate for a further 

 ten days. 



Numerous instances have since come under 

 my notice. Hen Chaffinches become so absorbed 

 that they fall to the ground and there continue 

 the struggle. Seizing hold of one another by 

 the feathers of the head, they roll from side to 

 side, and then, without relaxing their grip, he 

 exhausted^the quickened heart-beat, altered 

 respiration, tightly compressed feathers and 

 partially expanded wings betraying the intensity 

 of the conflict.. 



As the breeding season approaches, hen 

 Blackbirds grow more pugnacious. Individuals 

 that early in the year have frequented the same 

 spot daily and have even shown every sign of 

 friendship, become openly hostile. For two 

 years in succession I had an opportunity of 

 observing females under such conditions, and 

 of studying the gradual change in their relation- 

 ship. Each morning at break of day and for 

 some hours afterwards they could be seen in the 

 same place, one following the other as they 

 searched for food first in this direction and then 

 in that, as if they derived some special pleasure 

 from the fact of their companionship. Then a 

 change began to manifest itself. Indications of 

 animosity became apparent ; one would run 



