National Museum, 5; Boston Society, 3; Philadelphia Academy, 9; Coll.
G. N. Lawrence, 2; Museum Comp. Zoöl., 1; New York Museum, 5. Total, 25.
_Measurements._
+----+-----------+-----------+---------+---------+-----------+----------+
|Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.|Specimens.|
+----+-----------+-----------+---------+---------+-----------+----------+
| ♂ |14.35–14.75| 8.80–10.00| .91–1.00|2.20–3.00| 1.95–2.15| 9 |
+----+-----------+-----------+---------+---------+-----------+----------+
| ♀ |16.25–16.50|10.00–11.50|1.00–1.05|2.30–2.70| 2.00–2.25| 10 |
+----+-----------+-----------+---------+---------+-----------+----------+
Var. sacer, FORSTER.
MacFARLANE’S GERFALCON.
_Falco sacer_, FORSTER, Phil. Trans. LXII, 1772, 383 and 423.—COUES,
Birds of New England, 1868, 6.—BAIRD, Trans. Chicago Acad. Sc. I, ii,
271. _? Falco cinereus_, GMEL. Syst. Nat. p. 267, 1789.
SP. CHAR. _Adult_ (♂, 51,689, Yukon, mouth of Porcupine River;
Strachan Jones). Whole upper surface with numerous transverse bands
of brownish-plumbeous and ashy-white. Anteriorly the light bars are
about half the width of the dark ones; posteriorly they gradually
increase, the bands of the two colors being about of equal width on the
upper tail-coverts and tail; with the increase of the lighter bars,
they become more ashy, and, correspondingly, the darker ones are more
plumbeous; on the rump there is but little contrast between the bands
of the two, causing a prevalent bluish cast. The bands are everywhere
continuous, the light ones being interrupted only by the black shaft;
there are generally on the anterior portions about three light bars on
each feather, the last always terminal. Tail tipped with white, and
crossed with equal continuous bands of hoary-plumbeous and ashy-white;
the latter eleven in number, and finely sprinkled with deeper ash.
Primaries brownish-plumbeous, plain past the middle portion, but on the
anterior half with quadrate spots of creamy white on the outer web.
Head above brownish-plumbeous, this prevailing; but along the median
line the feathers are edged with buffy white; forehead dull white, this
continuing back in a streaked superciliary stripe to the occiput; cheeks
very thinly marked with fine streaks of dusky, this prevailing along
the upper border of the ear-coverts; a deeper dusky suffusion beneath
the anterior angle of the eye. Lower surface pure white; chin and
throat, only, immaculate; jugulum with very sparse, narrow longitudinal
streaks of blackish; sides with scattered cordate or nearly circular
spots, these larger and transverse on the flanks and tibiæ; abdomen
with scattered minute elliptical spots; lower tail-coverts with minute
irregular sagittate or transverse spots of dusky. Under surface of
the wing white; each feather of the lining with a medial tear-shaped
streak of dusky; primaries crossed with narrow bars of dusky, fifteen in
number on the longest. Wing-formula, 2–3–4–1–5. Wing, 13.50; tail, 8.60;
culmen, .90; tarsus, 2.15; middle toe, 1.87.
♀ (43,139, Fort Anderson, May 24, 1864, “♀ and two eggs”; R.
MacFarlane). Generally similar to the male. Head above conspicuously
streaked, but the dusky prevailing. Above the transverse bands are less
regular and continuous, anteriorly the plumbeous largely prevailing;
posterior portions, however, as in the male, but on the rump the bands
are more distinct. Beneath, the markings are more numerous, larger, and
broader; those on the jugulum linear; those of the abdomen medially
elliptical; laterally they are transversely cordate, and on the flanks
in form of broad transverse spots, or broad bars; on the tibiæ and lower
tail-coverts they form regular transverse bars,—on the latter, quite
distant. Wing-formula, 2–3–4, 1. Wing, 15.50; tail, 9.50; tarsus, 2.15
and .80; middle toe, 1.95.
_Juv._ (♂, 55,400, Alaska, Nulato, February 10, 1868; W. H. Dall).
Above plumbeous-umber, precisely as in young of _islandicus_, but on
the rump having a decided ashy cast. No white edges to the feathers,
as in _islandicus_, but, instead, numerous irregular transverse spots
or obsolete ragged bars of cream-color or pale ochraceous-buff; the
whole upper surface is quite thickly variegated with these irregular
markings. Tail crossed with thirteen narrow bands of creamy-white, these
so thickly mottled with dusky on the outer webs as to be obscure, but on
inner webs they are regular and sharply defined; the last is terminal.
Primaries plain dusky, skirted obscurely with paler, and marked toward
bases with obsolete mottled spots of cream-color. Head streaked with
dusky and creamy-white, the former predominating on upper surface,
along upper edge of ear-coverts, and across the cheeks, on the latter
forming a mustache; the white prevails over the ear-coverts in a broad
supra-oral stripe, and on the forehead and lores. Beneath, soft dull
white; chin and upper part of throat, only, immaculate; each feather
with a broad medial stripe of clear dark plumbeous-brown, on the flanks
and tibiæ prevailing, the whitish assuming the form of roundish spots;
lining of the wing similarly marked; prevailing aspect of under surface
of primaries white, crossed with narrow bars of ashy, fifteen in number
on the longest. Wing-formula, 2, 3–1=4. Wing, 14.00; tail, 8.40.
HAB. Interior regions of Arctic America; Anderson River, McKenzie,
Yukon, and Severn River regions. Breeding abundantly in the former
district, whence numerous specimens of skins and eggs have been received
by the Smithsonian Institution.
In the young specimen described, there are one or two new feathers
appearing on the rump and upper tail-coverts, precisely as in the blue
plumage, and proving conclusively their relationship. The species is as
different from the Iceland bird in the young stage as in the mature.
The most readily apparent differences are, lack of sharp white edges of
feathers above, and in their stead numerous ragged transverse spots of
yellowish; dark aspect of head above, etc.
Specimens vary considerably in the shades of color and distribution of
the markings, but the types of the above descriptions are the lightest
of the series. The darkest example is No. 43,144½ (“♀ and eggs”),
Fort Anderson, May 22, 1864. In this the whole head and neck (except
underneath) are continuous blackish-plumbeous, only the middle of the
auriculars being faintly streaked; the back is nearly plain dusky, and
even on the wings the bars are very obscure and much reduced in width.
The rump is plain ashy-blue, the darker bars being nearly obsolete.
The longitudinal markings on the pectoral region are enlarged into
conspicuous stripes, while on the sides and flanks the transverse bars
form heavy spots. The transverse bars on the tibiæ are ashy-blue; those
on the crissum clear plumbeous, and regularly transverse. Wing, 15.75;
tail, 9.30. Upon comparing this specimen with the figures of a pair of
var. _gyrfalco_, by Wolf, in Newton’s Oötheca Wolleyana, I can discover
no difference at all; thus it would seem that our bird occasionally
closely approaches in tints and markings this race of Continental
Europe, of which I have seen only one immature example, and no adults.
I cannot agree with Mr. Newton in considering the Gerfalcons of the
interior of Arctic America as identical with the Iceland form, though
that distinguished ornithologist considers them so in his paper in the
Proceedings of the Philadelphia Academy for July, 1871, basing his
conclusion upon the specimens from which the above descriptions were
taken, which had been sent over to England for comparison. I have never
yet seen a specimen of _islandicus_ which could not be distinguished,
by the characters given in my synopsis, from these examples, while they
can be separated from that race by the characters which Mr. Newton
himself gives, in his diagnostic table in the paper above cited, for
distinguishing the adults of _islandicus_ and _gyrfalco_.
The var. _sacer_ is evidently separable from both _islandicus_ and
_gyrfalco_, and about as much related to one as to the other; combining
the size and proportions of the former with the colors of the latter,
while in the wide amount of individual variation of plumage its lighter
extreme approaches one, while its darkest phase approximates as closely
to the average plumage of the other.