_Bonasa_, STEPHENS, Shaw’s Gen. Zoöl. XI, 1819. (Type, _Tetrao
bonasia_, L.)
_Tetrastes_, KEYS. & BLAS. Wirb. Europ. 1840, p. lxiv.
GEN. CHAR. Tail widening to the end, its feathers very broad, as long
as the wings; the feathers soft, and eighteen in number. Tarsi naked in
the lower half; covered with two rows of hexagonal scales anteriorly,
as in the _Ortyginæ_. Sides of toes strongly pectinated. Naked space on
the side of throat covered by a tuft of broad soft feathers. Portion of
culmen between the nasal fossæ about one third the total length. Top of
head with a soft crest.
This genus, in its partly naked tarsi, with two rows of scutellæ
anteriorly, indicates a close approach to the American Partridges, or
Quails. It has a single European representative, the _B. sylvestris_,
Steph.
Species and Varieties.
=B. umbellus.= Rump with cordate light spots; sides with transverse
dark spots. Tail with two gray bands (one terminal), with a broad
blackish zone between them. Cervical tufts glossy black or dark brown,
with a semi-metallic steel-blue or green border.
Prevailing color bright ochraceous-rufous; tail always rufous in
the Middle and Southern States, occasionally gray on the Alleghany
Mountains, and in New England States; usually gray in Eastern
British America. _Hab._ Eastern Province of North America …
var. _umbellus_.
Prevailing color bluish-ashy; tail always pale ash. _Hab._ Rocky
Mountains of United States, and interior regions of British America,
to the Yukon …
var. _umbelloides_.
Prevailing color dark ferruginous; tail always dark ferruginous
near the coast, occasionally dark gray in mountainous regions.
_Hab._ Northwest coast region (Oregon, Washington, British Columbia,
etc.) …
var. _sabini_.
The above synopsis is intended to present in the simplest form the
characteristic features of the three definable races of this exceedingly
variable species, as exhibited in a light rusty rufous-tailed form
of the Atlantic States, a pale gray ashy-tailed form of the Rocky
Mountains of the United States and British America, and a dark rusty
rufous-tailed form of the northwest coast region. These three, when
based on specimens from the regions where their characters are most
exaggerated and uniform, appear sufficiently distinct; but when we
find that specimens from the New England States have the rufous bodies
of _umbellus_ and gray tails of _umbelloides_, and that examples from
Eastern Oregon and Washington Territory have the dark rusty bodies of
_sabini_ and gray tails of _umbelloides_, and continue to see that
the transition between any two of the three forms is gradual with
the locality, we are unavoidably led to the conclusion that they are
merely geographical modifications of one species. The continuity of
the dark subterminal tail-band in _umbellus_, and its interruption in
_umbelloides_,—characters on which great stress is laid by Mr. Elliot
in his monograph, above cited,—we find to be contradicted by the large
series which we have examined; neither condition seems to be the rule in
either race, but the character proves to be utterly unreliable.
In the less elevated and more southern portions of the Eastern Province
of the United States, as in the Mississippi Valley and the States
bordering the Gulf and South Atlantic, the rufous type is prevalent;
the tail being always, so far as the specimens we have seen indicate,
of an ochraceous-rufous tint. Specimens with gray tails first occur
on the Alleghany Mountains, and become more common in the New England
States, the specimens from Maine having nearly all gray tails. Specimens
from Labrador approach still nearer the var. _umbelloides_,—the extreme
gray condition,—and agree with Alaskan specimens in having more brown
than those from the interior portions of British America or the Rocky
Mountains of the United States. More northern specimens of the inland
form have, again, a greater amount of white than those from the south or
coastward. Passing southward from Alaska toward Oregon, specimens become
darker, until, in the dense humid forests of the region of the Columbia,
a very dark plumage, with little or no gray, prevails, most similar to,
but even more reddish and much darker, than the style of the Southern
States of the Eastern Province. Passing from the low coast forests to
those of the mountains, we find again equally dark specimens, but with
grayish tails; the amount of gray increasing, and its shade lightening,
as we approach the central Rocky Mountains.
The American species of _Bonasa_ possesses a quite near analogue in the
_B. sylvestris_, Bonap. (_Tetrao bonasia_, Linn.), or Hazel Grouse, of
Europe. This species has almost exactly the same pattern of coloration
(including tail-markings), but is very much smaller, has the neck-tufts
rudimentary and white, and the throat black, instead of just the
reverse.
Bonasa umbellus, var. umbellus, STEPHENS.