STERC011A.RIUS. 329 



Genus STERCORARIUS, Brisson, 1760. 

 Characters of the family. 



Key to tlie Species. 



ft. Wing about 13: median rectrices pointed . 8. crepidatus, p. 329. 

 b. Wing 14 ; median rectrices rounded at end. pomatorhinus, p. 330. 



1518. Stercorarius crepidatus. Richardson's Skua. 



Larus crepidatus, Banks in Cook's Voy. (Hawkesivorth's ed.) ii, p. 15 



(1773) (descr. nulla) ; Gmel. S. N. i, p. 602 (1788). 

 Stercorarius parasiticus, apud Schaejfer, Mm. Orn. p. 62, pi. 37 



(1789) ; Hume, S. F. i, p. 268 ; nee Linn. 

 Stercorarius crepidatus, Vieill. Nouv. Diet. d'Hist. Nat. xxxii, p. 155 ; 



Saunders, Cat. B. M. xxv, p. 327. 

 Stercorarius asiaticus, Hume, S. F. i, p. 270 ; Butler Sf flume, S. F. 



\, p, 294 ; Hume, Cat. no. 977 ter ; Barnes, Birds Bom. p. 422. 



Fig. 74. Head of S. crepidatus, immature, f . 



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 

 &. 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 



