82 Mr. A. G. More on the Distribution of Birds 
Larus Marinus (Linn.). Great Black-backed Gull. 
Provinces I. VI. VII.? XII.—XIV. XVI. XVIII. 
Subprovinces 1, 2, 17, 18?, 25-28, 32-38. 
Lat. 50°-61°. “Scottish ” type, or Northern. 
It is only in the north of Scotland that the Great Black- 
backed Gull is at all numerous. The few localities in which it 
has been found breeding in England are scattered along the 
west coast, from Cornwall to Cumberland. I cannot find any 
recent authority, except Yarrell, for its breeding in the marshes 
at the mouth of the Thames. 
STERCORARIUS CATARRHACTES (G. R. Gray). Great Skua. 
Province XVIII. 
Subprovince 38. 
Lat. 60°-62°. “Scottish” type, or Northern. Not in Ireland. 
Only in the Shetland Isles, where the nest has long been 
known ; and here the bird extends to the island of Unst, which 
lies a little beyond latitude 61°. 
SrerRcorarivs parasiticus (G. R. Gray). Arctic Skua. 
Provinces [XVI.} XVII. XVIII. 
Subprovinces (33), 35-38. 
Lat. 57°-61°. “Scottish” type, or Northern. 
Pennant formerly found the Arctic Skua breeding in the 
Islands of Islay, Jura, and Rum; and it is probable that a few 
pairs may still linger in some of the numerous islands of this 
district, though Mr. H. D. Graham tells me that the bird is 
quite extinct in Jura. In Thompson’s ‘ Birds of Ireland? (vol. ii. 
p. 390) mention is made of a pair which were shot in 1837 in 
the Isle of Rum, where it is likely they had a nest. 
The bird still breeds in Sutherland and Caithness, and in all 
three groups of the Scottish Isles. ; 
STERCORARIUS cEPPHUS (G. R. Gray). Long-tailed Skua. 
Provinces XVII. XVIII. 
Subprovinces 35, 36, 37. 
Lat. 57°-61°. “Scottish” type. Not in Ireland. 
Respecting a former breeding-station in Caithness, Mr. R. 
J. Shearer, of Ulbster Housewick, has favoured me with the 
