136 A CATALOGUE OP THE BIKDS 



This species varies in the same maimer as Eichardson's Skua, 

 having, like it, dark and pale varieties, not influenced by age or 

 sex. 



11. Eichaebson's Sktja. S. paeasitictts, {LimicEUs.) 



Ledris Ricliardsonu, Bewick, Hist. Brit. Birds, Ed. 1847, II., 



219, 221. 



,, Yarrell, Hist. Brit. Birds, Ed. 2, III., 611. 



An autumn and winter visitant, common in September and 

 October ; generally flying with the Terns, and preying on their 

 industry and skill. It rests on the water, quietly watching the 

 movements of the Terns, and as soon as the fish is captured the 

 Skua make its appearance on the wing and goes in pursuit of the 

 successful fisher ; the chased bird screams with fear, and lets fall 

 its prey, which is seized by the pilferer before it reaches the sea. 

 On this the Terns disperse, and the Skua settling on the water 

 again awaits its opportunity. 



This sj)ecies varies much in plumage. It is sometimes entirely 

 of a dark dusky colour, and sometimes has most of the under parts 

 white, while the upper parts are dusky ; and between these two 

 extremes specimens occur of every depth of tint ; the under parts 

 in different specimens becoming by degrees paler until they are 

 entirely white, excepting a pale dusky band across the breast and 

 vent. These varieties are all adult birds, and are in no degree 

 influenced by age or sex. Dark and pale varieties occiu' in the 

 nest plumage ; at this early stage, however, the feathers of both 

 the back and the under parts are tipped with russet brown, pro- 

 ducing a transversely barred appearance. The neck and head 

 are longitudinally streaked Avith the same colour, and the front 

 half of the toes is black. 



While in ISTorway, in 1833, I had a good opportunity of study- 

 ing the varieties of this bird. We found it breeding on an island 

 near Torgluitten. One of the parents of a nest which we took 

 ■was entirely of a dark dusky colour, the other had the under 

 parts ^^'hite ; both parents of another nest were entirely dark. 

 Kichardson's Skua docs not breed associated in colonies, as most 

 of tlic L;nid;r do, but in scattered pairs. It was therefore quite 



