_Buteo krideri_, HOOPES, P. A. N. S. Philad. 1873, p. —
SP. CHAR. _Adult._ Similar to var. _borealis_, but beneath continuous
pure white, without rufous tinge, and without distinct spots across
the abdomen, or lacking them entirely; above much lighter, the brown,
light rufous, and white being about equal in amount. Upper tail-coverts
immaculate white; tail pale rufous, the shafts pure white, and the webs
mixed with white along their edges, its amount increasing toward the
base; no trace of a dusky subterminal bar, or else only indicated by
badly defined spots.
_Young._ Differing from that of var. _borealis_ in the immaculate,
snowy-white lower parts, nearly equal extent of the white and dusky on
the upper parts, and whitish cast of the tail.
Two females (one shot from nest of two eggs, near Alexandria, Minn.,
May 8, 1872,[87] and the other, also shot from nest of two eggs, near
Pelican Lake, Minn., May 21, 1872[88]) are entirely absolutely pure
white beneath, there being but the faintest indications of markings in
the region of the usual abdominal belt; even the whole under side of the
wing is almost immaculate. The ground-color of the upper parts is pale
grayish-brown, about equally variegated transversely, on the scapulars
and tertials, with white. In one of them, the sides of the head and neck
are pale fawn-color, the “mustache” from the rictus brownish-black in
conspicuous contrast; the upper parts are nearly equally variegated with
brown, light rufous, and white, the latter predominating posteriorly.
The upper tail-coverts are immaculate white. The tail-feathers are light
rufous, with pure white shafts, considerably mixed with white along the
edges of the feathers, the white considerably increasing towards the
base of the tail. Of the subterminal dusky band there is no trace in one
specimen, while in the other it is indicated by transverse spots, while
the inner webs along the shafts are much variegated with transverse
dusky spots. The male specimen (shot at Chippewa Lake, Minn., from nest
(!) of two eggs May 19, 1872[89]) is considerably darker, nearly like
the average plumage of eastern var. _borealis_. Still the white of the
lower parts is remarkably pure, being of an almost snowy clearness,
without any trace whatever of an ochraceous tinge.
No. 8,532, Devil’s River, Texas (Nov. 1855; Dr. C. B. Kennerly), differs
only in being a little less pure white beneath, the lower parts being
very appreciably tinged with rufous posteriorly.
HAB. Plains of the United States, from Minnesota to Texas (Devil’s
River, M. S. I.).
Var. lucasanus, RIDGWAY.