_Turdus aliciæ_, BAIRD, Birds N. Am. 1858, 217, plate 81, f. 2.—IB.
Review Am. Birds, I, 1864, 21.—COUES, Pr. Ac. N. Sc. Aug. 1861,
217 (Labrador).—IB. Catal. Birds of Washington.—GUNDLACH,
Repertorio, 1865, 229 (Cuba).—LAWR. Ann. N. Y. Lyc. IX, 91 (Costa
Rica).—DALL and BANNISTER, Birds Alaska.—RIDGWAY, Report.
SP. CHAR. Above nearly pure dark olive-green; sides of the head
ash-gray; the chin, throat, and under parts white; purest behind.
Sides of throat and across the breast with arrow-shaped spots of dark
plumbeous-brown. Sides of body and axillaries dull grayish-olivaceous.
Tibiæ plumbeous; legs brown. Length, nearly 8 inches; wing, 4.20;
tail, 3.20; tarsus, 1.15.
HAB. Eastern North America to shores of Arctic Ocean, and along
northern coast from Labrador to Kodiak, breeding in immense numbers
between the mouths of Mackenzie and Coppermine. West to Fort Yukon and
Missouri River States. Winters south to Costa Rica. Chiriqui, SALVIN;
Cuba, GUNDLACH.
As originally described, this species differs from _swainsoni_ in
larger size, longer bill, feet, and wings especially, straighter and
narrower bill. The back is of a greener olive. The breast and sides of
the head are entirely destitute of the buff tinge, or at best this is
very faintly indicated on the upper part of the breast. The most
characteristic features are seen on the side of the head. Here there
is no indication whatever of the light line from nostril to eye, and
scarcely any of a light ring round the eye,—the whole region being
grayish-olive, relieved slightly by whitish shaft-streaks on the
ear-coverts. The sides of body, axillars, and tibiæ are
olivaceous-gray, without any of the fulvous tinge seen in _swainsoni_.
The bill measures .40 from tip to nostril, sometimes more; tarsi, 1.21;
wing, 4.20; tail, 3.10,—total, about 7.50. Some specimens slightly
exceed these dimensions; few, if any, fall short of them.
In autumn the upper surface is somewhat different from that in spring,
being less grayish, and with a tinge of rich sepia or snuff-brown,
this becoming gradually more appreciable on the tail.
A specimen from Costa Rica is undistinguishable from typical examples
from the Eastern United States.
HABITS. This species, first described in the ninth volume of the
Pacific Railroad Surveys, bears so strong a resemblance to the
Olive-backed Thrush (_T. swainsoni_), that its value as a species has
often been disputed. It was first met with in Illinois. Since then
numerous specimens have been obtained from the District of Columbia,
from Labrador, and the lower Mackenzie River. In the latter regions it
was found breeding abundantly. It was also found in large numbers on
the Anderson River, but was rare on the Yukon, as well as at Great
Slave Lake, occurring there only as a bird of passage to or from more
northern breeding-grounds.
In regard to its general habits but little is known. Dr. Coues, who
found it in Labrador, breeding abundantly, speaks of meeting with a
family of these birds in a deep and thickly wooded ravine. The young
were just about to fly. The parents evinced the greatest anxiety for
the safety of their brood, endeavoring to lead him from their vicinity
by fluttering from bush to bush, constantly uttering a melancholy
_pheugh_, in low whistling tone. He mentions that all he saw uttered
precisely the same note, and were very timid, darting into the most
impenetrable thickets.
This thrush is a regular visitant to Massachusetts, both in its spring
and in its fall migration. It arrives from about the first to the
middle of May, and apparently remains about a week. It passes south
about the first of October. Occasionally it appears and is present in
Massachusetts at the same time with the _Turdus swainsoni_. From this
species I hold it to be unquestionably distinct, and in this opinion I
am confirmed by the observations of two very careful and reliable
ornithologists, Mr. William Brewster of Cambridge, one of our most
promising young naturalists, and Mr. George O. Welch of Lynn, whose
experience and observations in the field are unsurpassed. They inform
me that there are observable between these two forms certain
well-marked and constant differences, that never fail to indicate
their distinctness with even greater precision than the constant
though less marked differences in their plumage.
The _Turdus aliciæ_ comes a few days the earlier, and is often in full
song when the _T. swainsoni_ is silent. The song of the former is not
only totally different from that of the latter, but also from that of
all our other Wood Thrushes. It most resembles the song of _T.
pallasi_, but differs in being its exact inverse, for whereas the
latter begins with its lowest notes and proceeds on an ascending
scale, the former begins with its highest, and concludes with its
lowest note. The song of the _T. swainsoni_, on the other hand,
exhibits much less variation in the scale, all the notes being of
nearly the same altitude.
I am also informed that while the _T. swainsoni_ is far from being a
timid species, but may be easily approached, and while it seems almost
invariably to prefer the edges of the pine woods, and is rarely
observed in open grounds or among the bare deciduous trees, the habits
of the _T. aliciæ_ are the exact reverse in these respects. It is not
to be found in similar situations, but almost always frequents copses
of hard wood, searching for its food among their fallen leaves. It is
extremely timid and difficult to approach. As it stands or as it moves
upon the ground, it has a peculiar erectness of bearing which at once
indicates its true specific character so unmistakably that any one
once familiar with its appearance can never mistake it for _T.
swainsoni_ nor for any other bird.
The nests measure about 4 inches in diameter and 2¾ in height. The
cavity is 2 inches deep, and its diameter 2½ inches. They are
unusually compact for the nest of a thrush, and are composed chiefly
of an elaborate interweaving of fine sedges, leaves, stems of the more
delicate _Equisetaceæ_, dry grasses, strips of fine bark, and decayed
leaves, the whole intermingled with the paniculated inflorescence of
grasses. There is little or no lining other than these materials.
These nests were all found, with but few exceptions, on the branches
of low trees, from two to seven feet from the ground. In a few
exceptional cases the nests were built on the ground.
Occasionally nests of this species are found constructed with the base
and sides of solid mud, as with the common Robin (_Turdus
migratorius_). In these, as also in some other cases, their nests are
usually found on or near the ground. So far as I am aware neither its
occasional position on the ground, nor its mud frames, are
peculiarities ever noticeable in nests of _T. swainsoni_.
The eggs were usually four in number. Their color is either a deep
green tint, or green slightly tinged with blue; and they are marked
with spots of russet and yellowish-brown, varying both in size and
frequency. Their mean length is .92 of an inch, and their mean breadth
.64. The maximum length is .94 and the minimum .88 of an inch. There
is apparently a constant variation from the eggs of the _T.
swainsoni_; those of the _aliciæ_ having a more distinctly blue ground
color. The nests are also quite different in their appearance and
style of structure. The _Hypnum_ mosses, so marked a feature in the
nests of _T. swainsoni_, as also in those of _T. ustulatus_, are
wholly wanting in those of _T. aliciæ_.
This bird and the robin are the only species of our thrushes that
cross the Arctic Circle to any distance, or reach the shore of the
Arctic Ocean. It occurs from Labrador, all round the American coast,
to the Aleutian Islands, everywhere bearing its specific character as
indicated above. It is extremely abundant on and near the Arctic
coast, between the mouth of the Mackenzie River and the Coppermine,
more than 200 specimens (mostly with their eggs) having been sent
thence to the Smithsonian Institution by Mr. MacFarlane. In all this
number there was not a single bird that had any approach to the
characters of _T. swainsoni_, as just given. From the Slave Lake
region, on the other hand, _T. swainsoni_ was received in nearly the
same abundance, and unmixed during the breeding season with _T.
aliciæ_.
Turdus swainsoni, CABANIS.