head Dwicut, The Philadelphia Vireo. 267 
syllables when heard close at hand and the inflection rises slightly 
on the latter. A pause follows, approximating one and two fifths 
seconds, and the first note is again repeated, less forcibly and 
slightly varied. Again the pause ensues, and now it is followed 
by a triple note, not interrogatory and indistinguishable from one 
of V. olivaceus. Again the pause, this time followed by a repeti- 
tion of the triple note, slightly varied so as to lose some of its 
sibilance, and after the customary pause of one and two fifths 
seconds, the song is repeated from the beginning, nearly eight 
seconds having elapsed in completing one cycle. The four notes 
may be suggested by the syllables chur-rwé, chur-wé, pst'-i-ré, 
psr'-r-ré. The sequence of the notes, however, may vary a little, 
owing to the occasional substitution of one for the other, but the 
same one is not repeated more than twice in succession, even after 
a break in the continuity of the song. Heard at a distance, it 
practically reduces to two alternated notes, which I find repre- 
sented in my note books of different years as chi-wip, tir-i-dip 
in one place and /si-wii’rt, psi-wi-fit in another. The discrepan- 
cies are instructive, showing independent efforts on my part 
to lay hold of the same sound. 
The speed at which the song flows on is an interesting factor 
and is remarkably uniform for each individual songster, — in fact, 
I could almost identify certain Philadelphias and Red-eyes by 
timing their songs. V. philadelphicus sings at the rate of from 
twenty-two to thirty-six notes a minute, averaging a trifle over 
twenty-six, while V. o/vaceus rattles on at the rate of from fifty to 
seventy, their song rate averaging a trifle over fifty-nine. I do 
not mean to assert that there were always just so many notes in a 
given minute, for both species pause irregularly and drop out 
notes now and then, but if all were uttered in the same cadence 
as those actually heard, these figures would be equaled, and, in 
fact, very often are equaled. They are, however, only to be 
satisfactorily obtained at the height of the song period, and but 
for the careful use of a stop-watch I would hardly feel justified 
in presenting them. Some individuals are better songsters than 
others, but all follow more or less closely the type I have 
endeavored to describe. The song is sometimes a softer and 
disjointed affair and this soliloquizing type is characteristic of 
the wane of the song period. 
