A STUDY OF THE SINGING OF OUR BIRDS. 
BY EUGENE P. BICKNELL. 
( Continued from. p. 218.) 
Vireo flavifrons. Yellow-throated Vireo. 
This Vireo sings through July, August, and the early days of 
September. Records of song in some years are not closely con- 
secutive during the middle weeks of July, and again towards the 
end of August; but usually occasional songs prevent any signifi- 
cant break in the record. If, however, the summer be exceed- 
ingly hot and dry singing may be suspended for weeks at a time. 
Almost every year a few songs are to be heard in September, a 
week or two after singing has apparently ceased. In 1878 sing- 
ing continued with some regularity until September 7, after 
which songs from single birds on the 12th and 18th were the last ; 
in 1880 nothing was heard of the species between August 29 and 
September 12 — on the latter date, as well as on the 17th and 
18th, full songs being heard ; in 1881, September 6 and 19 limit 
a hiatus in the record, though on the latter date, as well as on the 
24th — my latest record— songs loud and full were heard. Mr. 
Brewster has observed somewhat similar habits of late song with 
this species at Cambridge, his latest record being September 1 1. 
This is the only one of our Vireos which I have observed to 
sing while on the wing. On May 21, 1882,1 observed a pair 
flying about among an open group of trees ; one was being fol- 
lowed by the other : but their motions betrayed none of the ex- 
citement of pursuer and pursued : their flight was so easy and 
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 fact 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 jieaceably among the branches, the follower 
alighting first. Attk, I. Oct. , 1884 . p. 3ZZ~3Z3 
