_Tetrao obscurus_, AUD. Orn. Biog. IV, 1838, 446, pl. ccclxv.—IB. Syn.
1839, 283.—IB. B. Am. I, 1842, 89.—NUTT. Orn. I, 1840, 609.—SWAINS.
F. B. A. II, 1831, 344, pl. lix, lx. _Tetrao richardsoni_, DOUGL.
Linn. Trans. XVI, 141.—LORD, Pr. R. A. I. IV, 122 (between Cascade and
Rocky Mountains).—GRAY, Cat. B. Brit. Mus. V, 1867, 86. _Dendragapus
richardsoni_, ELLIOT, P. A. N. S. 1864, 23.—IB. Monog. Tetraon,
pl.—WILSON, Illust. 1831, pl. xxx, xxxi.
SP. CHAR. Tail-feathers broad and nearly truncated; tail almost
perfectly square, and black to the tip, with the terminal band either
only faintly indicated or entirely wanting; in all other respects
exactly like var. _obscurus_. _Male_ (18,397, Browns Cut off. N. Rocky
Mountains; Lieutenant Mullan). Length, about 20.00; wing, 9.00; tail,
7.30; tarsus, 1.70; middle toe, 1.85. _Female_ (18,398, forty miles west
of Fort Benton; Lieutenant Mullan). Wing, 8.60; tail, 6.00; tarsus,
1.60; middle toe, 1.60.
HAB. Rocky Mountains of British America, south to the Yellowstone and
Hellgate region of the United States.
No. 18,377, Hellgate, and others from localities where this form and
var. _obscurus_ approach each other, have the terminal zone of the tail
of the usual width, and even sharply defined; but it is so dark as to be
scarcely distinguishable from the ground-color.
HABITS. In regard to distinctive peculiarities in habits and manners,
of this form of Grouse, if it possesses any, our information is quite
limited. In its external markings and in size it appears to be readily
distinguishable from the _T. obscurus_ either specifically or as a
well-marked interior race. Mr. J. K. Lord refers to it in his account
of the _obscurus_, where he states that between the Cascades and the
Rocky Mountains the Dusky Grouse appears to be replaced by a well-marked
variety, if not a distinct species. In size it is a trifle smaller, but
the great mark of distinction is the entire absence of the white band at
the end of the tail. In their habits, in their periods of arrival and
departure, or rather of appearance and disappearance, the two varieties
are pronounced to be, in every respect, similar. In regard to their
unexplained disappearance and reappearance, Mr. Lord is of the opinion
that these birds do not migrate, but only retire into the thickest
trees, and, living on the buds, pass the winter thus sheltered in the
tree-tops.
Captain Blakiston thinks that this species is the form that inhabits the
interior of British North America, and refers the figure of the male in
Richardson’s _Fauna_ to the _richardsoni_,—the Black-tailed and smaller
species. In his wanderings he met with these birds only in or near the
pine woods on the slopes of the Rocky Mountains; but, having killed
only females, he could not feel certain of the species. These Grouse
range towards the Pacific as far as the Cascade Mountains of Oregon and
British Columbia, and along the Rocky Mountains from the head-waters
of the Platte to the Liard River, a tributary of the Mackenzie. When
the ranges of the two species are fully defined, he thinks the _T.
richardsoni_ will be found the more northern bird.
The eggs of _Tetrao richardsoni_ are very similar, except in size, to
those of the _obscurus_, resembling them closely in their ground-color,
as well as in their markings. In the specimens in the cabinet of the
Boston Natural History Society the spots are smaller, a little less
distinct, and less numerous. The eggs are 1.75 inches in length, and
from 1.35 to 1.36 inches in breadth.