_Vireosylvia philadelphica_, CASSIN, Pr. A. N. Sc. V, Feb. 1857,
153.—IB. VI, pl. i, fig. 1 (Philadelphia).—SCLATER & SALVIN, Ibis,
I, 1859, 12 (Guatemala).—BAIRD, Rev. Am. Birds, 340. _Vireo
philadelphicus_, BAIRD, Birds N. Am. 1858, 335, pl. lxxviii, fig.
3. _Vireosylvia cobanensis_, SCLATER, P. Z. S. 1860, 463
(Coban).—IB. Ann. Mag. N. H. 1861, 328.
[Line drawing: _V. philadelphicus._
4364]
SP. CHAR. (No. 20,643 ♂.) Above dark olive-green, tinged with
plumbeous-ash except on the rump; top of head and nape purer
plumbeous-ash, not edged with dusky, the line of demarcation
indistinct. Beneath light sulphur-yellow, paler and almost white on
chin and middle of abdomen; sides more olivaceous. A whitish stripe
from bill over eye, as also a patch beneath it and the eyelids. A
dusky loral and post-ocular spot. Quills and rectrices brown, edged
externally with olive, internally with whitish; the larger coverts
with paler outer edges. Bill blackish, paler plumbeous below. Legs
plumbeous. Spurious outer or first quill (seen in _gilva_) wanting;
the outer about equal to fifth; third longest; second and fourth not
much shorter. Total length, 4.80; wing, 2.60; tail, 2.25.
HAB. Eastern North America to Hudson’s Bay and Maine, south (in
winter) to Costa Rica and Guatemala. Veragua (SALVIN). Not recorded
from Mexico or West Indies.
Specimens vary somewhat in purity of tints, and especially in
intensity of yellow of under parts, which color is deeper in autumnal
skins.
Specimens from Costa Rica and Guatemala, being merely winter visitors
to that region, are quite identical with North American examples.
HABITS. This but little known species was first described by Mr.
Cassin, in 1851, from a specimen shot by him in some woods near
Philadelphia nine years previously, which was then unique, and
remained so for some time after. This fact, and its resemblance to _V.
gilva_, led to the impression that it might be only a variety of that
species. Since the publication of the description other specimens have
been procured from different localities,—Moose Factory, Maine, Ohio,
Wisconsin, Costa Rica, and Guatemala. But little is as yet known in
regard to its habits or its distribution. It is quite abundant in the
spring in Southern Wisconsin, where it appears only as a migrant
passing north, none remaining to breed. As it makes its appearance
late in May, and usually passes rapidly on, it seems natural to infer
that it cannot be far from its breeding-place at the period of its
appearance. The specimen obtained by Mr. Cassin was shot in September,
on its southward journey. It was in the upper branches of a high tree,
capturing insects; and his attention was drawn to it by its slow and
deliberate movements.
Mr. Thure Kumlien, of Dane County, Wis., informs me that he has been
familiar with this Vireo since 1849, and has collected it every year
since that period, finding it both in the spring and fall. It appears
occasionally as early as the 10th of May, the time varying with the
season from the 10th to the 27th. In 1857, when the season was very
backward and May very cold, they did not arrive until June 2. They
were unusually numerous, and remained only a day or two. So far as he
has been able to ascertain, none stop to breed. They are very quiet,
have no song at the time they are passing, and seem only intent on
collecting their food and in proceeding on their way. They are very
tame and unsuspecting, and one can readily get to within a few feet of
them. In the fall they are returning south from the 7th to the 19th of
September.
The nest and eggs remain to be obtained.
Vireosylvia gilvus, CASSIN.