1SS4.J BiCKNELL on the Singing of Birds. ^23 



leisurely that it was almost restful to watch them. For more than 

 a minute they continued slowly circling about among- the trees, 

 within a space of a few rods, passing in and out among the 

 branches ; several times the leading bird appeared about to 

 alight, but feeling its pursuer close at hand continued its course. 

 The rear bird was constantly giving utterance to its full song- 

 notes, which foct probably accounts for its uninterested manner 

 as pursuer ; for it seemed so engrossed with the feat of singing 

 during flight that it could give little heed to the chase. Both 

 birds finally alighted peaceably among the branches, the follower 

 alighting first. 



Vireo solitarius. Blue-headed Vireo. 



This is one of the few migrants which are regularly in song 

 while passing in the fall. Their characteristic, yet Virionine 

 song is visually the first indication of their appearance, and the 

 last of their presence with us. Its greatest range in time, in dif- 

 ferent years, is from September 18 to October 9. This Vireo 

 also sings while passing northward in the spring. 



Vireo noveboracensis. White-eyed Vireo. 



There appears to be no regular period of silence with this 

 Vireo, which is more or less given to vocalism through its entire 

 stay. In July and August, however, there seems to be a time of 

 minimum vocal vigor, when singing is intermittent, and some- 

 times appears to cease briefly altogether ; but there is no constant 

 rule, the birds appearing to be much influenced b}- varjing exter- 

 nal causes. A severe drought, as with other species, is unfavor- 

 able to song, and during the exceptional aridity of the summer of 

 18S1 singing seemed, at intervals, to be wholly discontinued. In 

 September, or by late August, the normal vocal vigor is regained ; 

 and sometimes singing becomes very general late in September, 

 shortly before its discontinuance with us, which dates from the 

 22d to the 30th, and is due to the departure of the bird. 



This Vireo possesses greater powers of song than ai-e generally 

 accorded it. Perhaps its want of recognition as a vocalist is 

 because it does not reveal its fullest capabilities in the sprino- 

 when birds are expected to do their best. All through the sprino- 

 and early summer we hear in low bushy places and on shrubby 



