POMATOBHINE & RICHARDSON'S SKUAS. 133 



have found rather than find it itself ; it will even attack and 

 kill other weakly Gulls. 



Food. Fish and animal matters found floating on the sea or 

 purloined from other birds. 



Nest. May. One brood. 



Site. In hollow in ground on high moorlands. 



Materials. Twigs, dry grass, moss, &c. 



Eggs. Two. Olive-brown, blotched and spotted with dark 

 brown and greyish brown. 



POMATOKHINE SKUA (Stercorarius pomatorhinus) . 



An uncommon autumn and winter visitor on our coast-lines. 

 It is smaller than the last, and is always distinct on account of 

 the two elongated central tail-feathers having their shafts 

 twisted, the result being that the end part of the web stands 

 vertical, and looks in flight as though it had a "bob" to it. 

 Breeds further north than these islands. 



ARCTIC OB RICHARDSON'S SKUA 

 (Stercorarius crepidatus). 



The commonest Skua in these islands, being a regular 

 visitor to our coasts in autumn and spring. It breeds in the 

 Shetlands, Orkneys, Sutherland, and Caithness. 



Plumage. Crown dusky. Cheeks, neck, and under parts 

 white, suffused with yellow ; remaining plumage dusky. Bill 

 horn-colour. Legs and feet black. Length 20 in. Female 

 similar. 



Observations. There are two forms of this species, one light 

 (above described), the other dark. As these two varieties inter- 

 breed, birds with plumage intermediate between the light and 

 dark forms are found. The young are also subject to some 

 variation in their immature plumage according to the variety 

 to which their parents belong. Nestling covered with sooty- 

 grey down, paler below. These also vary according to the 

 parents. 



Language. A cry like "mee " or " mee-avvk." 



Habits. Generally like the Great Skua, but it is gregarious. 



Food. Fish, either caught by itself or robbed from other 

 Gulls. Also preys on wounded birds. 



Nest. May or June. One brood. 



Site. Like the Great Skua. 



Materials. Like the Great Skua. 



Eggs. Two. Olive-brown or russet-brown, spotted and 

 blotched with dark brown and grey. 



