172 THE GULLS 



the tops, and hugging the shelter these afforded from the gale from 

 seaward that was blowing." It may be a coincidence, but this winter 

 was remarkable for the enormous shoals of sprats (Clupea sprattus) 

 which swarmed in the narrow tideway of the Upper Forth at 

 Kincardine, as well as higher up, to such an extent that they were 

 shovelled out on to the adjoining fields as manure in hundreds of 

 tons. It was noticed that the great invasion of Pomatorhine and 

 other skuas in October 1879 was also accompanied by the presence 

 of vast shoals of herrings and sprats off our east coast, 1 so that it 

 seems probable that the two events were connected with one another 

 in each case. Other important visitations of this species took place in 

 1876-77 and 1894-95, and during the terrible storms of January 1881 

 some forty-five or fifty specimens were brought into Yarmouth by the 

 fishing boats, probably for the most part from the Dogger Bank. 



By far the greater number of these birds are immature ; it is only 

 rarely that a specimen in adult plumage is recorded, but the great 

 preponderance of immature birds is partly accounted for by the long 

 period which this species takes to assume the fully adult plumage. 

 There is no reasonable doubt that it does not breed during the first 

 four years of its life, but the summer home of these immature birds is 

 practically unknown. Dr. Alfred Walter, while stationed at Whales 

 Point Harbour in East Spitzbergen from May 29 to June 7, 1889, 

 noticed that on his arrival all the glaucous-gulls were old birds in full 

 plumage. On May 30 the first immature birds appeared, a flock of 

 six and then a single bird, all heading due north. From this date 

 onwards many young birds in all stages of plumage, sometimes 

 accompanied by old birds, passed over in flocks, the largest of which 

 numbered from twenty to thirty individuals. 2 



Even in the immature state the glaucous-gull is not difficult to 

 recognise. In size it equals the great blackback, and has a steady, 

 soaring flight. The wings are less bent at the carpal joint than in the 

 other gulls, giving them the appearance of being more extended. 



1 Stevenson, Birds of Norfolk, iii. 351. " Journal fur Ornithologie, 1890, p. 243. 



