84 BIRDS. 



353. Rissa tridactyla (Z.). Kittiwake. 



Resident, breeding abundantly in the Flamborough range of 

 cliffs. Many retire south in autumn, though the species 

 is common on the coast in winter. 



Sab-fam. STERCORARIINM. 



354. Stercorarius catarrhactes (Z.). Common Skua. 



Periodical visitant, occurring off the coast in autumn, and 

 most frequently off Flamborough Head ; comparatively 

 rare elsewhere. There is one record of its occurrence in 

 the spring, at Flamborough, on the ist of March, 1868. 

 Has once been obtained inland, at York, 8th Oct., 1879. 



355. Stercorarius pomatorhinus {Tem?n.). Pomatorhine 



Skua. 



Periodical visitant, occurring off the coast in autumn. In 

 most years only one or two — in immature plumage — are 

 observed, principally at Flamborough. In October, 1879, 

 an irruption of considerable extent took place, both adults 

 and immature birds being extremely numerous on the 

 coast, and some were shot very far inland. Before the 

 date of this irruption, adult birds had been almost unknown 

 in the county. 



356. Stercorarius crepidatus {Banks). Richardson's 



Skua. 



Periodical visitant to the coast, in autumn, when it is numerous 

 off Flamborough, chiefly immature, old birds being un- 

 common. This species was extremely abundant with its 

 congeners in the great flight of 1879. Has occasionally 

 occurred as a straggler inland. 



357. Stercorarius parasiticus (Z.). BufFon's Skua. 



Casual visitant in autumn, very much less frequent than S. 

 pomatorhinus and S. crepidatus^ and although many — 

 mature and immature — were obtained during the memor- 

 able irruption of 1879, it was much less numerous than 

 they, and until then immature specimens only had been 

 obtained. Inland, one occurred at Strensall Common on 

 the 8th of October, 1879. 



