GLAUCOUS GULL. 219 



bird, and it also occurs regularly in the north-west of Ireland. 

 Elsewhere it is an uncommon straggler, but is doubtless more 

 frequent than would be supposed from the records ; it occurs 

 occasionally on the west coast. 



In size the Glaucous or " Burgomaster " Gull corresponds 

 with the Great Black-back, and may be distinguished from all 

 other large gulls, except the Iceland, by the absence of black 

 on the primaries ; the Iceland is about the size of the Herring- 

 Gull. The Glaucous is a very white-looking bird when mature, 

 and at all ages is pale ; its light-grey mantle is several shades 

 paler than that of the Herring-Gull. When at rest it may be 

 distinguished from the Iceland Gull by the relative shortness 

 of its wings, which when closed rarely project beyond the tail. 

 From even the Great Black-back it differs in its " steady soar- 

 ing flight," for it shows less angle in the wing than any other 

 gull ; indeed, its shape when at a height resembles rather a 

 Buzzard or other raptorial bird. There are " good " and " bad " 

 years for this species, and doubtless the irregularity in its 

 numbers is due to abundance or shortness of food caused by 

 climatic variation in the Arctic. Though it delights in dead meat, 

 and helps to dispose of the refuse turned out from the whaling 

 stations, it is even more predacious than the Great Black-back ; 

 it worries all birds smaller and weaker than itself, ripping them 

 to bits with its massive beak. It has been known to swallow 

 a Golden Plover without troubling to dismember it. Its calls 

 differ little from those of its congeners. 



The adult in summer is very pale grey on the back and 

 wings, and the rest of the plumage is white, including the tips 

 of the quills. In winter the head is faintly streaked with 

 brownish grey. The bill is yellow with an orange patch at the 

 angle ; the legs are pink, the irides yellow, and the eye-rims 

 vermihon. At first the young bird is pale buff, mottled, barred, 

 and streaked with ashy brown, lighter than any other gull in 

 corresponding plumage. With each moult the colour pales, 



