NATURAL HISTORY OF THE SWAINSON'S WARBLER 67 



are whisper songs, as far as I can ascertain. When singing the 

 primary advertising song, the bird changes the position of its 

 head more than that of its body. The body is only slightly angled 

 upward from the silent perching position; the head is thrown 

 back with the bill pointed upward at a sharp angle, although not 

 quite perpendicular. (Bird artists who have attempted to portray 

 a singing bird of this species have usually done so incorrectly.) 

 The bird's head and body are not tilted upward when singing 

 muted or whisper songs. 



The Swainson's Warbler sings from the ground, and from trees, 

 shrubs, vines, and logs, usually below 30 feet. I have heard a bird 

 singing from a perch as high as 50 feet, but singing from such a 

 height is very uncharacteristic. 



Singing from the ground is usually sporadic, since it is done 

 while hunting for food. The bird nearly always stops to sing when 

 foraging along the ground, assuming virtually the same posture 

 as when singing from a branch; sometimes it starts singing be- 

 fore coming to a complete halt. After a male has spent some time 

 on the ground intermittently foraging and singing, he may fly 

 to the limb of a tree, where he rests, preens, or continues singing. 



During the first few days after they arrive on the breeding 

 grounds, birds in the canebrakes of the Ocmulgee River floodplain 

 forest sing much more often from the ground than from trees or 

 shrubs. In 40 hours of observation, three of four individuals were 

 observed to sing only from the ground during their first week, 

 April 12-19, 1965. During April 12-15, 1966, soon after the birds 

 had arrived on the breeding grounds, one male sang only from 

 the ground when under observation for 10 hours. When I next 

 observed this bird, on April 28, it sang also from trees. Another 

 male sang 135 songs from the ground and 65 from trees when 

 under observation for 90 minutes on April 15. 



When the Swainson's Warbler sings from trees, some of the 

 perches most often used are dead branches well out from the 

 trunk in the lower parts of the trees. The bird sings from a sta- 

 tionary position when perched in a tree or shrub, as pointed out 

 by Brewster (1885a, p. 73-74) : 



While singing he takes an easier posture, but rarely moves on his perch. If 

 desirous of changing his position he flies from branch to branch instead of 

 hopping through the twigs in the manner of most warblers. 



However, a singing bird may reverse its position on the same 

 perch and resume singing while faced in the opposite direction. 



In the course of 1 hour a Charleston, W. Va., male sang from 

 18 perches, once only from each of 17, and five times from one. 



