224 SEA-BIRDS 



probably the skua in this instance was exceptionally hungry. During 

 ten days at midsummer 1948, from a trawler working the Rockall 

 Bank, we saw great skuas frequently, but they did not harry any birds 

 (and there were thousands of fulmars present), being apparently con- 

 tent to search for food far in the wake of the trawler, evidently taking 

 the roughest offal of the fish guttings which had been thrown out 

 plentifully and floated astern, after the bold fulmars in their hundreds 

 close to the ship had seized the livers and tender parts. 



Gulls and terns are the principal victims of the piracy of the skuas, 

 which seldom select a gull or tern that is incapable, through a long 

 fast, of throwing up a contribution ; in all probability the skua recog- 

 nises the appearance of a food-laden gull or tern (if the fish it is carrying 

 is not visible) by its more leisurely, less hunting flight. Skuas also 

 prey on smaller birds, both over the sea and the land; and if these 

 are unable to escape by taking cover or diving they are relentlessly 

 followed, tired out, killed and devoured. A pomarine skua has been 

 seen to pursue to the death a phalarope at sea (Bent, 1921): and to 

 force a fulmar to drop a fish, just south of the Newfoundland banks, 

 14 April 1 92 1 (Fisher, 1952). 



Some skuas may breed far inland, as in northern Europe and 

 Siberia; and the food then consists much of small mammals (lemmings 

 especially), small birds, eggs, freshwater fish, insects, worms, etc. 

 The great skua is probably the most marine and gull-like in its feeding 

 habits, living mainly on fish, pirated or legitimately taken, and killing 

 large and small birds, adult or young, along the seaboard of its nesting 

 area; and it is a gull-like scavenger of stranded carcases of seal, 

 whale, fish and other carrion. 



The breeding habits of the great and arctic skuas have been, and 

 are being, studied, but little is known about the lives of the pomarine 

 and long- tailed skuas. To their most southern nesting haunts the great 

 and arctic skuas return during April. The eggs are laid a month later. 

 Some of the display and posturing is similar to that of the Lams gulls, 

 including the food-begging actions and mating ceremonies. In court- 

 ship the male raises his wings and flutters them as he approaches the 

 female. He holds his head upwards and backwards and puffs out 

 the neck hackles, displaying with sharp excited calls in his effort to 

 gain her attention. She responds with a wheezing or hissing note, 

 sometimes standing upright and at other times bowing to the ground 

 as if to invite coition. The male continues for some time a kind of strut- 

 ting dance in a half-circle round his partner; and wing play goes 



