PHILADELPHIA VIREO 359 



minute on June 22 of the utterances of a bird singing this song from 

 the nest showed seventeen utterances to the minute, which I consider 

 to be quite the highest rate at which I heard this song delivered." 

 The discrepancy is perliaps due to the fact that lie was counting com- 

 plete songs, while Dr. Dwight was counting individual notes. 

 He says, of the song he counted : 



The song heard from the male from Juno 13 to June 22, inolnsive, was simple, 

 but delightful; a low, sweet, gentle "Doo-we? whe6-hooey; doo-we? whoe-hooey," 

 uttered slowly and with long intervals between one utterance and the next. 

 Sometimes the first utterance was elaborated into "Doodle-ee?", * * * 



On June 23, and often thereaftei', the male Philadelphia Vireo sang a song 

 altogether different from that which I have described. This new song was 

 loud and vigcirous, and was readily recognizable as a Vireo's song, although the 

 tone in which it was given was not quite so full as is the tone of the song of the 

 Red-eyed Vireo. It consisted of notes like "S-s-s-cApe! ee-oh-yuh ! ee-yoit! 

 cheeb-ly !', and perhaps one or two others, repeated over and over in different 

 orders. * * * 



On June 25, when the female had left incubation to feed, the male, while 

 following her through the lower branches of the trees, sang, in a loud voice, 

 "Chee-6w-y ! hee-iih !," over and over again. This song was heard at such times 

 only. Other loud songs which were heard often from this male after June 23 

 were "Whde-hoit ! s-s-s-jerry !" and "S-s-s-chew-ee ! wh^e-hooey !" After July 

 4 singing rapidly declined, the last song heard from this species being a few 

 loud notes on July 17, three days after I ceased to find the juvenals. * * * 



Other Philadelphia Vireos heard during the nesting-season sang similar loud 

 songs, but the songs of no two of them were exactly alike. * ♦ * j might 

 point out that many common song-phrases of the Red-eyed Vireo, such as its 

 plain little "Huh-huh," do not appear in any recognizable form in the songs of 

 the Philadelphia Vireos heard by me, and that this seems to provide one ready 

 means of distinguishing between the songs of the two species. 



He mentions, also, "a mouse-like squeaking, a scolding note, a fine 

 'It, it, it, it, it,' and (from the female only) a 'Mew, mew'. * * * 

 The 'Mew, mew' of the female apparentl}^ indicated readiness for 

 coition." 



Field marks. — A glance at the excellent colored plate published with 

 Dr. Dwighfs (1897) paper will show that the Philadelphia vireo 

 looks very much like a warbling vireo with a pale yellow breast but 

 slightly greener above and with the stripe over the eye less distinct. 

 It also looks like a red-eyed vireo, minus the gray cap, distinctly 

 bordered with dusky, and with more yellow beneath. The yellow 

 throat and breast of the yellow-throated vireo are a much deeper 

 yellow, and there are two white wing bars on each wing. From the 

 warblers, some of which have a similar color pattern, it can be dis- 

 tinguished by its heavier bill and stockier shape. 



Enemies. — We do not know much about the enemies of this vireo. 

 Dr. Friedmann (1934 and 1943) could find only two cases where it 

 was parasitized by cowbirds, one in Alberta and one in Ontario, by 

 the Nevada cowbird and by the eastern cowbird, respectively. Prob- 



