_Accipiter falco freti hudsonis_, BRIS. Orn. I, 356, 1763. _A.
gyrfalco_, BRISS. Orn. I, 370, pl. xxx, f. 2, 1763. _Falco
rusticolus_, FABR. Faun. Grœn. p. 55, 1780.—LATH. Syn. Supp. I, 15,
1781. _F. candicans_, GMEL. Syst. Nat. p. 275, 1788.—DAUD. Tr. Orn.
II, 101, 1800.—BENICK, Isis, 1824, 882.—SCHLEG. Krit. Ubers. p. 1,
1844.—BONAP. Rev. Zool. 1850, 484; Consp. Av. p. 33.—CASSIN, Proc.
Ac. Nat. Sc. Phil. 1855, 278; Birds N. Am. 1858, 13.—STRICKL. Orn.
Syn. I, 77, 1855.—BLASIUS, Cab. Jour. 1862, 43 (thinks all boreal
ones same in Europe and America).—ELLIOT, Birds N. Am. pl. xii.
_Hierofalco candicans_, CUV. Reg. An. ed. 1, I, 312, 1817; ed. 2, I,
323, 1829.—LESS. Man. Orn. I, 80, 1828; Tr. Orn. p. 97, pl. xvi, p.
2.—GRAY, Hand List I, 18, 1869. _Falco islandicus_, LATH. Ind. Orn. p.
32, 1790; Syn. I, 71, A, B; Gen. Hist. I, 72, A, 1821.—STEPH. Zool.
XIII, pt. ii, p. 39, 1826.—GOULD, B. Eur. pl. xix.—AUD. Birds Am.
1831, pl. ccclxvi. _F. buteo_ β, LATH. Ind. Orn. p. 24, 1790; Gen.
Hist. I, 80, A. _F. lagopus_, β, LATH. Ind. Orn. p. 19, 1790; Syn.
Supp. I, 36; Gen. Hist. I, 68, A. _F. grœnlandicus_, DAUD. Tr. Orn.
II, 157, 1800. _Hierofalco grœnlandicus_, BREHM. Voy. Deutsch, I, 16,
1831. _F. gyrfalco_, BONAP. List, p. 4, 1838.
SP. CHAR. _Adult_ (♀, 18,577, Greenland; Univ. Zool. Mus. Copenhagen).
Ground-color entirely pure white; whole upper surface (posterior to the
nape) with transverse crescentic bars of dark plumbeous-brown, generally
about two on each feather, the first concealed by the feather which
overlaps. Primaries crossed at regular intervals with quadrate spots
of the same tint, these becoming fused toward ends of quills, forming
a terminal dusky space of two or three inches in extent; tips of all
the quills narrowly white; the black bars do not extend quite to the
primary coverts, and decrease both in extent and regularity toward the
base. Middle tail-feathers crossed with seven or eight imperfect bars
of dusky, the shafts of the feathers blackish; rest of tail immaculate,
the shafts pure white. Nape with a very few fine shaft-streaks of dusky.
Whole lower surface of body and wing utterly immaculate. Wing-formula,
2–3–1. Wing, 16.50; tail, 9.00; culmen, 1.05; tarsus, 2.10–1.35; middle
toe, 2.20; inner, 1.50; outer, 1.50; posterior, 1.00.
(No. 56,152, ♀, Greenland; Schlüter Collection.) Head above, occiput,
nape, and upper half of ear-coverts, with sparse shaft-streaks of
black, these most numerous on the latter region; primaries barred to
the coverts. Tail entirely crossed by eleven plumbeous bars. Bars above
clearer plumbeous. The snowy-white beneath is relieved by a few minute
variable flecks of dusky upon the lower part of the abdomen, becoming
larger as they approach the sides. Wing-formula, 2–3–1. Wing, 16.70;
tail, 9.30.
_Juv. transition stage?_ (♂ 56,047, “Hoher Norden”; Schlüter
Collection). Markings above quite different from those of the two
preceding; each feather has a large central longitudinal sagittate spot
of dusky, leaving only the borders (of the exposed portion) white; on
the primaries the dusky is almost confined to the terminal portion;
the rump and upper tail-coverts have each feathers with a medial
longitudinal stripe of dusky. The tail is immaculate, but the shafts of
the middle feathers are dusky. The neck, breast, abdomen, and sides have
numerous cuneate marks of dusky, one near the end of each feather. The
lining of the wing, even, has a few narrow streaks. Wing, 14.75; tail,
9.40.
No. 56,049 (♀, Greenland, Schl. Coll.) is similar in pattern
of markings, but above the dusky is more extended, forming the
predominating color; the rump, etc., has broad sagittate spots instead
of narrow stripes; the primaries are barred to the coverts; the tail is
crossed by about ten continuous bands of dusky. Beneath the lanceolate
spots or streaks cover the whole surface, except the anal region, lower
tail-coverts, and throat. On the lining of the wing the streaks are less
sparse than in the preceding, though they are by no means numerous.
Wing, 15.75; tail, 9.50.
[Illustration: _Falco candicans._]
_Juv. first plumage_ (♀, 56,053, Greenland; Schlüter Coll.). All the
markings are longitudinal, instead of directly the reverse. The upper
parts have longitudinal tear-shaped stripes, a medial one on each
feather; they are sparse, however, on the wings; the rump has narrow
shaft-lines of dusky. The tail and upper coverts are immaculate, but
the shafts of all the feathers are nearly pure black. The bars on the
primaries are found only immediately next the dusky terminal space. The
streaks beneath are not very numerous, and are found only on the breast,
upper part of abdomen, and on the sides; the nape and sides of the neck
are, however, thickly streaked.
(No. 17,966, ♀, Moose Factory, Hudson Bay Territory.) In character of
markings resembling the last, but the stripes are fainter and narrower;
they are also less numerous. On the under parts they are wanting.
Unfortunately, the tail of this specimen, which is the only North
American one in the collection, is missing.
In all specimens the anal region and lower tail-coverts are immaculate.
HAB. Greenland, and continent of North America, north of Hudson
Bay (breeding in latter region). Of irregular occurrence in winter
throughout the circumpolar regions; Ural Mountains (EVERSMAN); Behring’s
Strait (BANNISTER).