_Vireosylvia plumbea_, COUES, Pr. A. N. Sc. Phila. 1866 (Fort Whipple,
near Prescott, Arizona).—COOPER, Orn. Cal. 1, 1870, 119.—ELLIOT,
Illust. Birds N. A. I, vii. _V._ (_Lanivireo_) _plumbea_, BAIRD,
Rev. 349.
SP. CHAR. (No. 37,011.) Whole upper parts and sides of head uniform
plumbeous; the lower part of the back with a faint wash of olivaceous.
A white line from bill to and around eye; a dusky line from corner of
eye to bill. Sides of breast and flanks plumbeous, paler than the
back; the flanks very slightly tinged with olive-green. Rest of under
parts white; the axillars ashy, edged with white. Wings above with two
conspicuous white bands; the innermost quills edged externally and the
longer ones internally with white, the latter edged externally with
light ash. Bill and legs dark plumbeous, “Iris hazel.” Tail-feathers
narrowly edged all round with white, narrowest internally, and
increasing from central to lateral feathers. Upper tail-coverts clear
ash.
[Line drawing: _Vireosylvia plumbea._
37010]
As the specimen in finest plumage (described above) is moulting the
quills, the measurements are taken from another (37,010). In this the
first quill is not quite one third the second, which equals the sixth,
the third and fourth longest.
(No. 37,010.) Fresh specimen: Total length, 6.10; expanse of wings,
10.80. Prepared specimen: Total length, 5.75; wing, 3.25; tail, 2.70;
difference between tenth and longest quill, .95; exposed portion of
first primary, .75, of second, 2.34, of longest, third (measured from
exposed base of first primary), 2.54; length of bill from forehead,
.55, from nostril, .31, along gape, .70; tarsus, .75; middle toe and
claw, .60, claw alone, .21; hind toe and claw, .50, claw alone, .23.
HAB. Southern Rocky Mountains; East Humboldt Mountains, Nevada
(RIDGWAY). In winter to Colima, Mexico.
While the pattern of coloration is precisely similar to that of
_Lanivireo solitarius_, the difference in the colors appears to be
occasioned merely by removing, as it were, the yellow stain, which on
the plumbeous produces the olive-green tinge, and exists in a purer
tint along the sides, leaving, essentially, only clear plumbeous and
pure white; there is, however, in the most typical specimens, always a
faint tinge of green on the rump, and a stain of yellow along the
side. Though identical with _solitarius_ in most of its proportions,
the wings and tail are considerably longer than in the average of that
form.
There are many specimens from the Rocky Mountains and westward that
are so decidedly intermediate between _solitarius_ and _plumbeus_,
that, considering also the lack of essential difference in form and
coloration between the two, we do not hesitate to consider them, along
with _cassini_ and _propinquus_ (see page 373), as races of a single
species, of which each is the representative in a particular region.
Thus, _V. solitarius_ breeds in the Eastern Province of the United
States (and possibly in the Western, following the same route far to
the northward that many Eastern birds pursue in straggling westward),
and migrates in winter into Middle America as far as Guatemala; those
which breed in the Northwest pass directly southward, thus crossing
the region where _cassini_ and _plumbeus_ breed, which accounts for
their being obtained together. _V. cassini_ is the representative on
the opposite side of the continent; but the history of its migrations
is yet obscure. _V. plumbeus_ is the Middle Province and Rocky
Mountain representative, breeding alone in that region, and in winter
migrating southward through Western Mexico as far as Colima. _V.
propinquus_ is another permanent race, but a local one, being resident
in the country where found, though mixed in winter with visitors of
_solitarius_ from the North.
HABITS. Of this very recently discovered race, very little is at
present known. It was first described by Dr. Coues, who met with it in
Arizona, near Fort Whipple. He says it is especially abundant in the
northern part of that Territory. It was by far the most common Vireo
at Fort Whipple, where it is a summer resident, arriving there about
the 15th of April and remaining until October.
It was found to be common about Laramie Peak, by Dr. R. Hitz, and was
also met with in winter on the plains at Colima, Mexico, by Xantus.
It was seen in the summers of 1868 and 1869, by Mr. Ridgway, among the
cedar and nut-pine woods on the slopes and among the brushwood in the
cañons of the East Humboldt Mountains, being most partial to the
former situations. There, too, it undoubtedly breeds, as in the latter
part of July young birds, unable to fly, were met with by him. He also
states that the common notes of this Vireo very closely resemble those
of the Western Wood Wren (_Troglodytes parkmanni_).
Lanivireo flavifrons, BAIRD.