Part 13

Coloration of the sexes alike at all ages; old and young slightly different in pattern and tints. Scutellæ of tarsus and toes uninterrupted from “knees” to claws; tarsus but little longer than middle toe. Bill large, the cere on top about one third the culmen. Size medium; form very slender …

_Rhynchofalco._

SUBGENUS HIEROFALCO, CUVIER.

_Hierofalco_, CUVIER, 1817. (Type, _Falco gyrfalco_, LINN.) _Jerafalco_, BOIE, 1822; KAUP, 1851. (Same type.) _Gennaia_, KAUP, 1847. (Type, _Falco jugger_, GRAY.)

Species and Races.

=1.= =F. gyrfalco.= Wing, 13.00–17.00; tail, 8.50–11.50; culmen, .85–1.05; tarsus, 2.10–3.00; middle toe, 1.80–2.25.[45] Ground-color varying from entirely pure white to wholly dusky, but generally bluish (in adult) or grayish-brown (in young) above, and white beneath. _Adult._ All the markings transverse.[46] No lighter nuchal band. _Young._ Markings of the lower surface longitudinal, the upper parts without transverse bars (except on the tail[47]).

_a._ Lower parts with white predominating, or wholly white.

Lower tail-coverts never with markings. No tinge of blue anywhere on the plumage, the ground-color of which is entirely pure white at all ages.

1. _Adult._ Upper parts, excepting head and neck, with transverse crescentic bars of dark plumbeous; lower parts immaculate, or else without well-defined markings. _Young._ Upper parts with longitudinal stripes of dark plumbeous; lower parts usually conspicuously striped. _Hab._ Greenland (in the breeding-season); in winter, occasionally wandering into the northern portions of Europe and North America …

var. _candicans_.

Lower tail-coverts always with markings. A tinge of ashy-blue more or less prevalent above. Young dusky above.

Head and neck above abruptly lighter than the back. Young plain grayish-brown above, with conspicuous whitish borders to the feathers.

2. _Adult._ Upper parts white, passing into bluish posteriorly; everywhere (except on head and neck) with sharply defined, transverse (not crescentic, but continuous) bars of dark plumbeous. Abdomen and flanks with transverse spots of the same. _Young_ without irregular light mottling to the plumage above, and with broad longitudinal stripes beneath. _Hab._ Iceland and Southern Greenland, in the breeding-season; in winter, south into Northeastern United States, and Northern Europe …

var. _islandicus_.

Head and neck above abruptly darker than the back. Young (of var. _sacer_) variegated grayish-brown above, without light borders to the feathers.

3. _Adult._ Top of the head streaked with whitish; back with sharply defined, continuous, narrow transverse bars, of creamy-white. _Hab._ Interior regions of Continental Arctic America (Slave Lake, Yukon, and McKenzie River district) …

var. _sacer_.

4. _Adult._ Top of head not streaked with whitish; back without sharply defined bars of the same. _Hab._ Continental Arctic Europe (Scandinavia) and Siberia. Migrating south, in winter, to Bengal (Hardwicke) …

var. _gyrfalco_.[48]

_b._ Lower parts with dusky predominating, or wholly dusky.

5. _Adult._ Almost entirely dusky, without well-defined markings anywhere. _Hab._ Littoral regions of the Hudson Bay Territory and Labrador …

var. _labradora_.

=2.= =F. lanarius.= Wing, 11.50–16.00; tail, 6.60–9.50; culmen, .70–1.00; tarsus, 1.90–2.40; middle toe, 1.65–2.00. Ground-color varying from pale grayish-plumbeous to dark sepia-brown; beneath white, with sparse markings, these coalesced into a broken patch on the flanks. _Adult._ Above obscurely barred transversely with pale ashy and brownish-dusky, the former prevailing posteriorly, the latter anteriorly; a lighter nuchal band. Spots on the sides and flanks transverse. _Young._ Above brown, varying from grayish-drab to dark sepia, the feathers usually bordered with paler (rusty in youngest individuals); markings beneath all longitudinal.

_a._ Outer webs of tail-feathers with large well-defined light spots; outer webs of the primaries sometimes with light spots on the basal portion; secondaries without distinct spots on the outer webs. Lower tail-coverts immaculate.

Wing, 13.65–16.00; tail, 8.40–9.50; culmen, .85–1.00; tarsus, 1.95–2.15; middle toe, 1.85–1.95. Top of the head white, with narrow streaks of dark brown. _Hab._ Central and Eastern Europe, Western Asia, and adjoining portions of Africa …

var. _lanarius_.[49]

_b._ Outer webs of tail-feathers without distinct light spots, or without any at all; outer webs of primaries with no trace of spots; secondaries with light spots on outer webs. Lower tail-coverts sparsely spotted.

Wing, 12.00–14.25; tail, 7.60–9.00; culmen, .75–.90; tarsus, 2.15–2.40; middle toe, 1.70–2.00. Top of head brown, with narrow black streaks. _Adult._ Above with obscure transverse spots of bluish. _Young._ Above with feathers bordered with rusty …

var. _polyagrus_.

Wing, 11.50; tail, 6.60; culmen, .70; tarsus, 1.90; middle toe, 1.65. Above uniform dark brown, with a faint plumbeous cast, the feathers without trace of light or rusty edges; outer web of tail-feathers without trace of light spots. _Hab._ Mexico …

var. _mexicanus_.[50]

Wing, 13.60–14.30; tail, 8.25–9.00; culmen, .80–.87; tarsus, 1.85–1.90; middle toe, 1.85–1.90. Colors similar to the last; entire auriculars white; mustache narrow and conspicuous. _Hab._ Southern Asia …

var. _jugger_.[51]

The only point of difference in the external anatomy between the Lanner Falcons and Gerfalcons consists in the different degree of feathering on the upper part of the tarsus; this is much denser and extends farther down and more around the posterior face in the Gerfalcons, but they, being inhabitants of a very northern latitude, need this protection against the rigor of the climate. These slight specific differences are illustrated by the figures on page 1430. The same difference is observable in many birds whose habitat extends through a great range of latitude, as, for instance, the _Pediocætes phasianellus_, the northern race of which has the feathers covering the base of the toes so long as to reach beyond the claws and nearly conceal them, while in the southern form (var. _columbianus_) the toes are almost completely naked.

My determination of the number and character of the geographical races of _F. gyrfalco_ is the result of a very careful critical examination of over sixty specimens, aided by the important conclusions of Mr. Hancock (Annals and Magazine of Natural History, 2d ser., XIII, 110; London, 1834), Schlegel (_Falcones_, Muséum d’Histoire Naturelle des Pays-Bas, 1862), Pelzeln (Uebersicht der Geier und Falken der Kaiserlichen ornithologischen Sammlung, April, 1863), and Alfred Newton (History of British Birds, revised ed., part 1, June, 1871, pp. 36–52, and Proc. Acad. Nat. Sc. Philadelphia, July, 1871, pp. 94, 95), in their important papers bearing upon this subject, which, though they each express the peculiar individual views of the writer, together clear up pretty satisfactorily the problem of the number, character, and habitats of the several races, as well as the different phases of variation to which each is subject.

In studying the _F. lanarius_, I have experienced most discouraging difficulties from the want of sufficient series of the Old World races, and from the unsatisfactory character of most descriptions and figures of them, besides being much perplexed by the confusion of their synonymy by different authors. In consequence of this, my diagnoses of the four races of which alone I have seen examples may be very unsatisfactory as regards the characters by which they may be most readily distinguished. Having seen the adult of only a single one of these four races, I am therefore compelled to base my differential characters upon the immature stages.

In addition to the four races of _F. lanarius_ characterized above, there are several geographical forms belonging to the Old World, chiefly intertropical Asia and Africa. These are the var. _babylonicus_, Scl. and Irby, (Gray’s Hand List, I, p. 20, No. 173,) of Southeastern Europe and Western Asia; var. _barbarus_, L. (Gray’s Hand List, p. 20, No. 174), of Northern Africa; and var. _tanypterus_, Licht. (Gray’s Hand List, No. 175), of both the preceding regions, which Mr. Gurney writes me “is simply the intertropical race of _F. lanarius_, from which it only differs in being of a darker shade throughout.” The _F. saker_, Schleg. (Gray’s Hand List, No. 176), seems, to judge from the descriptions and figures which I have seen, to be also merely a form of the same species, but I have seen no specimens of it.

Falco (Hierofalco) gyrfalco, LINN.

Var. =candicans=, GMELIN.

WHITE GERFALCON.

_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.

_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).

LIST OF SPECIMENS EXAMINED.

National Museum, 7; Boston Society, 2; Philadelphia Academy, 3; New York Museum, 6; collection of R. Ridgway, 1. Total, 19.

_Measurements._

+----+-----------+-----------+---------+---------+-----------+----------+ |Sex.| Wing. | Tail. | Culmen. | Tarsus. |Middle Toe.|Specimens.| +----+-----------+-----------+---------+---------+-----------+----------+ | ♂ |14.40–14.75| 9.70–00.00| .90–0.00|2.15–2.45| 1.95–2.00| 3 | +----+-----------+-----------+---------+---------+-----------+----------+ | ♀ |15.75–16.25|10.00–11.00| .98–1.00|2.20–2.50| 2.05–2.15| 6 | +----+-----------+-----------+---------+---------+-----------+----------+

Var. islandicus, SABINE.

ICELAND GERFALCON.

_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).

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.

LIST OF SPECIMENS EXAMINED.

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.