94 atxen's naturalist's library. 



Stercorarius pomatorhinus^ Dresser, B. Eur. viii. p. 463, pi. 610 

 (1877) ; B. O. U. List Brit. B. p. 194 (1883) ; Saunders, 

 ed. Yarrell's Brit. B. iii. p. 668 (1884); id. Man. Brit. B. 

 p. 673 (1889) ; id. Cat. B. Brit. Mus. xxv. p. 323 (1896). 



Stcrcorarius poniarinus^ Seebohm, Hist. Brit. B. iii.p. 349 (1885). 



Adult Male.— General colour above dark slaty-bro^vn, the 

 lateral upper tail-coverts with some white bars, mostly con- 

 cealed ; wing-coveits like the back ; bastard-wing, primary- 

 coverts, and quills blackish-brown, browner on the inner w^eb, 

 and with a good deal of white at the base of the latter, 

 decreasing in extent on the inner primaries ; tail blackish- 

 brown ; crown of head black, forming a cap, the black 

 extending over the lores, feathers below the eye and fore part 

 of cheeks ; the feathers of the occiput acuminate like those of 

 the hind neck, which is straw-yellow like the sides of the face 

 and sides of the neck; the hind-neck slaty-brown like the 

 back, but mottled with white bars ; throat straw-yellow like the 

 sides of the neck, the chin w^iiter; remainder of under surface 

 of body white, the lower throat and fore-neck mottled thickly 

 wath black bars and edgings to the feathers, the sides of the 

 body and flanks also mottled in the same way ; the lower 

 abdomen and under tail-coverts nearly uniform slaty-brow^n, 

 only slightly mottled with white ; under wing-coverts and 

 axillaries uniform slaty-brown, the lower primary-coverts lighter 

 slate-grey ; bill horn-brown ; tarsi and toes reddish-brown. 

 Total length, 21 inches; culmen, 17; wing, i4'6 ; tail, 4*9 ; 

 centre tail-feathers, 7 '5; tarsus, 2-1. 



Adult Female. — Similar to the male. Total length, 20-5 

 inches ; wing, 14*0. 



Adult in Winter. — Similar to the summer plumage, but for 

 some years after the attainment of adult — though not mature 

 — plumage, there is a tendency, after the autumnal moult, to 

 show striated feathers on the flanks, as well as on the upper and 

 under tail-coverts. (Saunders, Cat. B. xxv. p. 326.) 



The pectoral band is wider in immature birds, the yellow 

 on the neck is not so evident, and the flanks are generally 

 streaked. There are more bars on the under surface of the 

 body, and the upper and under tail-coverts, as well as the 

 under wing coverts, are barred or mottled with black and 



