_Accipiter falco islandicus_, BRISS. Orn. I, 336, 1763. _Falco
islandicus_, SAB. Linn. Trans. XII, 528, 1818.—TEMM. Man. Orn. pt.
x; 17, pt. iii, p. 9; Tab. Meth. p. 2, 1836.—FABER, Prod. Island.
Orn. 1822, p. 2; Isis, 1827, 62.—RICH. & SWAINS. F. B. A. II, 27,
1831.—HOY, Mag. Nat. Hist. Ser. 1, VI, 107.—HANCOCK, Ann. Nat. Hist.
II, 247; Rev. Zoöl. 1839, 123.—BONAP. Consp. Av. p. 24.—STRICKL.
Orn. Syn. I, 77, 1855.—CASSIN, Birds N. Am. 1858, 13. _Hierofalco
islandicus_, GRAY, Gen. B. p. 3 (ed. 2, p. 4), 1844; Hand List, I, 18,
1869. _Falco candicans islandicus_, SCHLEG. Krit. übers, p. 1, 1844.
_Falco lanarius_, FABER, Isis, 1827, 68. _Falco gyrfalco_, KEYSERLING
& BLASIUS, Wirbelth. Eur. p. 135, 1840.
SP. CHAR. _Adult_ (♂, Iceland; No. 12, Coll. Geo. N. Lawrence).
Ground-color of the plumage dull white, gradually becoming somewhat
bluish posteriorly, this color especially noticeable on the tail. Whole
upper parts crossed with broad transverse bands of dark plumbeous,
these bands continuous, and more than twice as wide as the pale ones,
except on the upper tail-coverts and tail, where the bands of the two
colors are more regularly defined and about equal; in addition to the
transverse bands, the feathers anteriorly have narrow borders of white.
Tail with the dark bands twelve in number; the terminal pale band
is purer white than the others. The dusky plumbeous prevails on the
primaries, and is unvariegated beyond the middle portion; the anterior
half, however, is marked with quadrate ragged spots, of a slightly
yellowish-white; all are margined terminally with purer white. Each
feather of the head and neck with a narrow medial streak of dusky, but
the general aspect abruptly lighter than the back; the streaks are more
condensed along the upper and terminal portion of the ear-coverts.
Jugulum and breast with a medial narrow streak on each feather; abdomen
with more elliptical streaks; sides with circular and cordate spots, and
flanks and tibiæ with transverse spots; lower tail-coverts with narrow
shaft-streaks of dusky. Lining of the wing with sparse narrow streaks of
dusky; under surface of primaries with white prevailing, this, however,
crossed by narrow bars of dusky, these numbering about sixteen on the
longest. Wing-formula, 2–3–1. Wing, 14.60; tail, 7.80; culmen, 1.00;
tarsus, 2.30; middle toe, 2.00.
_Juv._ (No. 20,344, Iceland). Ground-color of head, neck, and lower
parts, white. Upper surface grayish umber-brown, becoming paler and more
grayish on the tail; each feather above sharply bordered (both webs, all
round) with dull white, producing a somewhat squamate appearance; in
places, a few obsolete hidden spots of yellowish-white. Tail ashy-drab
(feathers somewhat paler along edges), crossed with about eleven
transverse series of spots of ochraceous or creamy white; these very
obsolete on middle feathers, and sharply defined only on inner webs;
the last is terminal. Primaries plain brown, somewhat darker than the
back, and becoming insensibly darker terminally; skirted with white,
and somewhat mottled or irregularly spotted toward their bases with
yellowish-white. Head and neck, each feather, with a medial streak
of dusky, but white the prevailing aspect; these streaks condensed
and somewhat suffused along upper border of ear-coverts, and from the
lores along cheeks, forming an obsolete “mustache”; every feather
beneath (including lining of wings) with a medial broad stripe of
clear plumbeous vandyke-brown, the shaft pure black; under surface of
primaries with transverse spaces of white, these numbering thirteen on
the longest. Wing-formula, 2–3, 1. Wing, 15.00; tail, 9.20.
HAB. Iceland and Southern Greenland. Northeastern North America in
winter, straggling accidentally south to the New England States; Rhode
Island (Museum, Cambridge); Norway, Maine “not uncommon” (VERRILL);
Massachusetts (PEABODY & JILLSON); Long Island (CAB., G. N. LAWRENCE).
[Illustration: _Falco islandicus._]
No. 56,050, Greenland (Schlüter Collection), is moulting, and assuming
the adult dress; the adult and young stages above described being nearly
equally combined. No. 56,055, from Greenland, differs from the other
young individuals which I have seen in being considerably darker. The
feathers of the upper surface are not bordered with whitish, but are
merely paler on their edges, along which are specks of yellowish. On the
head and neck the dark streaks predominate, while the stripes below are
very broad. It approaches quite nearly toward the young of var. _sacer_.
The only specimen of this race which I have seen from Continental North
America, is a young individual, obtained during the winter of 1864–65,
near Providence, R. I., taken by Mr. Newton Dexter, and now in the
Cambridge Museum, where I had the pleasure of seeing it.