RICHARDSON'S OR ARCTIC SKUA. 257 



inches beyond the others. It is smaller than the Pomatorhine, 

 which has the elongated feathers rounded, and larger than 

 Buffon's, which has very much longer streamers. Immature 

 birds, before the tails have lengthened, are very puzzling, 

 especially when in flight, but in the hand one character usually 

 holds good — the shafts of the primaries. Saunders points out 

 that in the Arctic all the primaries have white shafts, but in 

 Buffon's only the first two, those of the inner primaries being 

 dusky ; after examining a number of skins I am inclined to 

 agree with his American critics that this rule has exceptions, 

 and that the distinction between white and dusky is at times 

 fine. 



On the wing the Arctic Skua is graceful, its flight being 

 steady and regular, varied with hawk-like glides, but when 

 chasing a gull, tern, or diving bird, for it victimises the 

 Guillemot and Puffln, it is erratic, swift, and powerful. When 

 the hunted bird throws up food, the swoop of the Skua is 

 wonderfully smart, yet if it misses the desired tit-bit it seldom 

 tries to recover it from the water, but turns its attention to 

 another victim. Some assert that it always hunts in couples, 

 one bird worrying its dupe and the other fielding the food, 

 but I have often seen a single Skua following a tern. When, 

 however, a shoal of sand-eels or fry has attracted large numbers 

 of gulls, terns, and auks, three or four Arctic Skuas will attend 

 on the outskirts of the noisy crowd, commandeering whenever 

 opportunity offers. On the moors insects and berries are eaten, 

 and Saxby states that small waders are killed and devoured. 

 On several occasions I have noticed a light, even white 

 patch, at the base of the primaries of the flying bird, and 

 Mr. R. W. Jones and Mr. T. Hadfield have observed the same. 

 In most skins the white basal portion of the primaries is con- 

 cealed by the coverts, but in one I could just see it ; this white 

 is often exposed when the wing is extended as in the Great 

 Skua. The ordinary call is well described as mewing, but it is 

 Series II. S 



