1518. Stercorarius crepidatus.
Larus crepidatus, Banks in Cook's Voy. (Hawkesworth's ed.) ii, p. 15 (1773) (descr. nulla); Gmel. S. N. i, p. 602 (1788). Stercorarius parasiticus, apud Schaeffer, Mus. Orn. p. 62, pi. 37 (1789) ; Hume, S. F. i, p. 268; nee Linn. Stercorarius crepidatus, Vieill. Nouv. Dict. d'Hist. Nat. xxxii, p. 155 ; Saunders, Cat. B. M. xxv, p. 327. Stercorarius asiaticus, Hume, S. F. i, p. 270; Butler & Hume, S. F. v, p. 294 ; Hume, Cat. no. 977 ter ; Barnes, Birds Bom. p. 422.
Coloration. Crown, nape, lores, and sides of head to beneath the orbit, with a patch at the side of the lower mandible below the gape, dark brown, darker behind, but passing into whitish at the base of the bill; cheeks, ear-coverts and their neighbourhood, lower parts to vent, and a narrow collar round the neck (sharply defined in front, but not behind) white; throat and collar more or less tinged with glossy straw-colour, and very often a pale brown gorget across the upper breast; all upper parts from the neck, the wings above and below, tail, lower tail-coverts, feathers around vent, thigh-coverts, flanks, and axillaries dark brown ; all shafts of primaries white.
There is also a dark variety, which is dark brown throughout, generally rather paler below than above, and tinged with yellow round the neck. Intermediate forms, with more or less of the lower surface brown, also occur.
Young birds are dark brown above, the edges of many feathers mottled with rufous ; lower parts brown, chin to fore neck streaked with paler brown ; rest of lower plumage irregularly barred with brown and white or rufous. In a further stage (as in the type of S. asiaticus) the upper parts are blackish brown, the crown streaked whitish, hind neck and back more or less barred and fringed with the same, and some of the upper, tail-coverts broadly banded brown and rufescent white; lower parts white, with brown, rather irregular crossbars on sides of: neck, fore neck, breast, flanks, and lower tail-coverts.
Bill brown ; cere pale greenish brown; irides brown ; legs and feet dull black (Hume).
Length about 20 ; tail without middle pair of feathers 5, the middle feathers 1 to 3 inches longer; wing 13 ; tarsus 1.75; bill from gape 2.
Distribution. This Skua breeds in Arctic and Subarctic regions, down to lat. 55°, and is found in winter in many parts of the world, ranging as far south as New Zealand, the Cape of Good Hope, and Bio Janeiro. It is by no means rare at that season on the Makran and Sind coasts, and some were seen by Captain Butler as late in the year as June. There can, I think, be no doubt that Mr. Howard Saunders was right in identifying S. asiaticus with Richardson's Skua.