Sua. NATATORES. CATARACTES. 521 
In its young state, as the Black-toed Gull (Larus crepi- 
datus) of authors, this species is not of unfrequent occur- 
rence, during the autumnal months, upon the northern coast 
of England; to which it is attracted by the Gulls that fol- 
low the shoals of herring on their approach to the shallows, 
for the purpose of depositing their spawn. Like the other 
Skuas, it obtains the greater part of its subsistence by con- 
tinual warfare on the above-mentioned birds; vigorously 
pursuing and harassing them till they are compelled to dis- 
gorge the food previously swallowed. In this occupation its 
dark plumage and rapid flight are certain to attract the at- 
tention of the spectator; and there are few probably who 
have visited the coasts of Scotland, and the northern districts 
of England, who have not witnessed and admired the aerial 
evolutions of the 7'eazer, and the distress of its unfortunate 
object of attack. It is but very rarely met with beyond the 
precincts of the Shetland and Orkney Isles in its adult state, 
and only one instance has occurred within my own observa- 
tion, viz. on an excursion to the Fern Islands in the month 
of May, when two of these birds flew ahead of the boat in a 
northerly direction; and which were perfectly distinguish- 
able by their lengthened and slender middle tail-feathers, 
and the black and white of their plumage. This Skua does 
not appear to be a permanent resident in any part of the 
British dominions, for Low, in his “* Fauna Orcadensis,” de- 
scribes it as a migratory bird, arriving there and in Shetland 
in May, and departing in autumn, or as soon as the duties 
of reproduction have been effected. From its absence, in 
the adult state, from our southern coast, it would seem that 
the line of its winter migration is more to the eastward; and 
this agrees with the statement of TrmMminck, who gives as 
its habitats the shores of the Baltic, of Norway and Sweden. 
—It breeds upon several of the Orkney and Shetland Isles, 
and is gregarious during that period; and the situations se- 
lected for nidification are the unfrequented heaths at some 
distance from the shore. The nest is composed of dry grass 
Periodical 
visitant. 
Food. 
Nest, &c. 
