212 BiCKNELL on the Singing of Birds. [July 



Helminthophila peregrina ( Wils.) Ridgw. Tennessee 



Warbler. 



The transient presence of this species, in the upper foliage of 

 the woodland in May, is usually revealed by its attractive song. 

 In the aiatumn it passes in silence. 



Compsothlypis americana (Z.) Cab* Blue Yellow- 

 backed Warbler. 



A constant songster on its spring migration, but ordinarily 

 silent in the fall, unless individuals sometimes cause exceptions 

 to the rule. I feel quite positive of having heard a faint song 

 on September i8, 1881, from one of a small party of these 

 birds ; but it was not repeated, and I could not verify my convic- 

 tion. A little farther north, however, the species does sing on 

 its return migration ; for I am told by Dr. E. A. Mearns that, 

 near West Point, he has sometimes found it in full song in the 

 autumn. 



The Blue Yellow-backed Warbler has two different songs. In 

 one the notes coalesce into a fine insect-like trill ; in the other 

 four similar notes are followed by four others, weaker and 

 more quickly given. 



This species arrives in the fall in full plumage, and somewhat 

 fat. The color of its fat is a very pale sulphury, in contrast to 

 that of other species, as the Nashville Warbler or the Redstart, 

 in which the fat is more opaque and of an orange or reddish 

 color. 



Dendrceca aestiva. Summer Warbler. 



Sings from its arrival in late April through July, but usually 

 with diminished frequency toward the end of the month, although 

 in some years it continues in full song nearly until mid- August. 

 Ordinarily singing ceases in the second week of August ; rarely 

 earlier, but sometimes later. Extreme dates are August 4, i;, 

 and 9, and August 18 and 19. This is the season of the bird's 

 departure. 



* Cf. Stejneger, Auk, Vol. I, pp. 169, 170. 



