THE POMATORHINE SKUA. 779 



build, and almost uniform brown colour, when seen at any distance, 

 give this species a rather heavy, lumbering look as it flies low over 

 the sea. At closer quarters white patch on wing (at bases of quills) 

 is readily seen. When in pursuit of other birds or while defending 

 its nest, the flight is much accelerated and becomes impressively 

 swift and powerful. As a rule rather silent, but occasionally utters 

 a deep " Gack, gack." (F.C.R.J.). 



Breeding-habits. — Breeds by preference in colonies, but not very 

 close together, and sometimes one or two pairs may be met with 

 far from any others. Nest. — Little more than a scantily lined 

 depression in heather, moss or rough pasture. Eggs. — Normally 2, 

 occasionally one, but 3 once recorded, usually pale olive-brown to 

 umber-brown, but occasionally bluish-green, in ground-colour, 

 blotched and spotted with dark umber-brown. Average of 100 

 eggs, 70.59x49.37. Max.: 78.55x50.6 and 71.5x53.2. Min. : 

 62x44.5 mm. Breeding -season. — Latter half May and early June. 

 Incubation. — By both sexes in turn. Period 28-30 days (Hantzsch). 

 Single brooded. 



Food. — Subsists on food disgorged by Gulls and Terns, but also 

 fishes for itself. At nesting ground herrings often found lying round 

 nest. Has also been known to kill Herring-Gull, Kittiwake, Duck 

 and Coot, and will feed on stranded fish and offal, such as carcasses 

 of whales. 



Distribution. — British Isles. — Breeds in Shetlands and Orkneys. 

 Much increased late years (breeds considerable numbers Foula and 

 Hermaness, also breeds Noss, Fetlar, Hascosay, Burrafirth Voe, and 

 probably elsewhere, also a few pairs in one of Orkneys since about 

 1914). Elsewhere winter-visitor (exceptional summer), seldom 

 coming to land. Seen various months at sea off south-west Ireland ; 

 others obtained Dublin, Down, and Tipperary, and one seen Meath. 



Distribution. — Abroad. — Breeds in Iceland and Fseroes. In 

 winter southward in north Atlantic to about Gibraltar, fishing- 

 grounds off Newfoundland and Nova Scotia, and even (casually) to 

 Long Island. Casual in Mediterranean (Italy), and recorded from 

 Madeira. Replaced by allied forms in southern oceans. 



STERCORARIUS POMARINUS 



462. Stercorarius pomarinus (Temm.) — THE POMATORHINE 

 SKUA. 



Lestris pomarinus Temminck, Man. d'Orn., p. 514 (1815 — Arctic 

 regions, Holland and France). 



Stercorarius pomatorhinus (Temminck), Yarrell, in, p. 668 ; Saunders, 

 p. 689. 



Description. — Adult male and female. Summer. — Pale form. — 

 Crown, nape, lores, base of lower mandible and under eye black 

 forming well defined cap ; sides and back of neck and ear-coverts 

 straw-yellow (feathers rather pointed and somewhat stiffened in 



