378 BIRDS OP TUNISIA 



Family STEECOEAKIID.E. 



STERCORARIUS CREPIDATUS (Banks). 



ARCTIC OR RICHARDSON'S SKUA. 



Larus crepidatus, Banks, in Cook's Voij., IlmckesicortJi' s Ed. ii, p. 15 



(1773). _ 

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



(1815) ; Saunders, Cat. Birds Brit. Mas. xxv, p. 327 ; Whitaker, Ibis, 



1898, p. 12G. 



Description. — Adult male, autumn, fi-om Island of Galita, North Tunisia. 



Upper parts blackish-brown, with the exception of the back and sides of 

 the neck, -which are whitish, washed with pale yellow; under parts whitish, 

 mottled and irregularly barred with brown, chiefly on the breast ; under 

 tail-coverts, flanks, under wing-coverts and axillaries whitish, broadly 

 barred with brown ; median rectrices tapering to a point and projecting 

 about two and a half inches beyond the rest ; shafts of the four outer 

 primaries white. 



Iris dark brown ; bill and feet blackish. 



Total length 18 inches, wing 13, culmen 1-40, tarsus 1-85. 



Adult female similar to the male. 



Young. — Forehead and crown ochreous, thickly striped with dark brown, 

 neck and least wing-coverts brighter and less striped with brown ; remainder 

 of the upper plumage dark brown ; under parts whitish, thickly striped 

 throughout with light brown ; under tail-coverts, flanks, under wing-coverts 

 and axillaries rufescent, broadly barred with brown. 



Observation. — The present species is subject to considerable individual 

 variation in plumage, but in addition to this there would appear to be two 

 fairly distinct varieties or races, one being of a uniform dark sooty colour, 

 the other having light under parts. 



This is the only member of the genus I have met with in Tunisia, 

 though both S. ixirasiticus and S. pomatorhinus are probably also to 

 be found there occasionally, and possibly even S. catarrhactes, as all 

 three species occur (more or less rarely) in the Mediterranean, and 

 Favier {fide Colonel Irby) records them all, as well as S. crepidatus, 

 from the neighbourhood of Tangier. 



Of the present species I have obtained examples, in winter, in the 

 neighbourhood of Tunis and at Tabarka, on the north coast of the 

 Regency. In the vicinity of the latter small island these Skuas were 

 not uncommon in December. 



