NATURAL HISTORY OF THE SWAINSON'S WARBLER 



51 



Figure 22. — Display of a male Swainson's Warbler during or immediately 

 following a boundary dispute with a neighboring male. The display re- 

 sembles a female soliciting copulation. The wings are quivered, the tail 

 feathers are alternately spread and closed, and the bird may step sideways 

 back and forth along the limb. 



There is usually little antagonism toward other species, and 

 vice versa. White-eyed Vireos, Prothonotary Warblers, Hooded 

 Warblers, Cardinals, and occasionally other species nest in terri- 

 tories of the Swainson's Warbler and, like the Swainson's War- 

 bler, live close to the ground. On one occasion I saw a Hooded 

 Warbler chase a Swainson's Warbler, after which the latter flew 

 to a high branch within its territory and sang vigorously for 

 about 10 seconds. 



COURTSHIP AND MATING 



I have never been present the minute the pair-bond was formed, 

 nor have I witnessed male courtship displays before pair forma- 

 tion. 



On one occasion when a female entered a male's territory for 

 what I believe was the first time, she was chased for short dis- 



