BUFFON'S SKUA. 259 



south in northern Atlantic and Pacitic oceans. It is less 

 frequent than the Pomatorhine and much rarer than the Arctic 

 Skua, appearing as a passage migrant in autumn, and occasion- 

 ally in spring, off our shores and inland. At times, in " skua 

 years," numbers arrive, stormy weather causing invasions ; the 

 greatest numbers have been observed on the east coast from 

 Yorkshire northward, but there are scattered records from all 

 parts. 



Long-tailed Skua is a descriptive name, for the literally 

 outstanding feature of the mature bird is the extraordinary 

 elongation of the two central tail feathers, which project for 

 from six to nine inches beyond the others. In general colour 

 pattern it resembles the light phase of the Arctic Skua, 

 but is rather greyer ; dimorphism has been recorded in this 

 species, but it is less variable than the last named. In 

 young birds, and all skuas take some years to attain perfect 

 plumage, the streamers are shorter, and, according to some 

 authorities, are more obtuse at the tip than in the Arctic, but 

 this is difficult to see in a living bird. The rule, however, that 

 the shafts of the two outer primaries only are white, the others 

 dusky, holds good in most cases. The Long-tailed is the smallest 

 and most elegant of the skuas ; its flight is lighter and more 

 graceful ; it glides through the air without effort, and often 

 hovers like a tern. Indeed, there is much that is suggestive 

 of a tern in its build and behaviour. Mr. J. A. Dockray, who 

 watched and photographed a bird at close quarters in Ireland 

 in the spring of 19 14, when others were met with in various 

 places in England, noticed a peculiarity which is difficult to 

 explain. The tips of the long streamers turned up and forward 

 when the bird was alighting, though held straight when on the 

 water ; the bird alighted and swam against a very light wind, 

 which he was sure did not influence the curve. In May, 1916, 

 Mr. F. W. Holder and a friend watched one in the Ribble 

 estuary, and without knowledge of Mr. Dockray's observations. 



