646 Bonaparte's gull. 



rence down to South Carolina, and occasionally visits the Bermudas ; 

 it is, however, rare on the Gulf side of Florida, and has not yet been 

 obtained in the West Indies. With the first genial weather in April 

 and throughout the greater part of ^lay there is a succession of birds 

 passing northward; ; the earlier ones being adults, while the later 

 arrivals are birds of the previous year, some of which linger on the 

 coast-marshes all the summer. Richardson, who found this species 

 breeding in the vicinity of Great Bear Lake, says that it is seen 

 there as soon as the first pools arc thawed, and before the ground is 

 denuded of snow. 



The above explorer and Messrs. MacFarlane, Kennicott &c. agree 

 in stating that Bonaparte's Gull builds in colonies, placing its nest, 

 which is composed of sticks, grass, moss &c., on the branches of some 

 bush or tree — often a spruce-fir — at elevations varying from four to 

 twenty feet ; in some districts, however, it appears to breed in 

 marshes, and, presumably, on the ground. The eggs, 2-3 in number, 

 are dull olive-colour, spotted, scrolled and zoned with brown : 

 average measurements i"9 by i"4 in., though there is considerable 

 variation in a large series. The food consibts of small fish, crusta- 

 ceans, insects and their larvre ; the flight is buoyant and Tern-like; 

 and the note is described as a "sharp but rather faint squeak." 



The adult in summer has a slate or greyish-black hood, pearl-grey 

 mantle, and white tail and under parts ; the outer web of the first 

 primary and the ends of the first five black, the remainder of those 

 feathers being white — or greyish — on the inner webs; bill black; 

 legs and feet orange-red. The se.xes are alike in plumage, and the 

 statements of Audubon and Bonaparte that the female has a brown 

 hood are inexplicable. In winter the head is nearly white. The bird 

 figured on the rock is an immature specimen in its first winter ; the 

 transitional stages are similar to those in other Gulls, and I need 

 merely state that at all ages this species may be distinguished by the 

 white margins to the i?mer webs of the i'cco outer pi'imaj-ies. Length 

 i4'5 in.; wing 10*25 i"- 



The American Laughing Gull, L. atricilla, was added to the 

 British list by Montagu in error, as indicated by his description of 

 the bird obtained at Winchelsea. This species is stouter than our 

 L. ridibiindiis, has a blacker hood and darker mantle, and may 

 always be distinguished by its black outer primaries. 



