LARUS MARINUS : GREAT BLACK-BACKED GULL. 347 



Another species occurring off the coast in winter, 

 but apparently one of the rarer gulls. It may, however, 

 be really more common than is supposed, as it closely 

 resembles the ordinary Herring Gull in size and general 

 appearance, excepting the black tips of the wings, and is 

 therefore liable to be overlooked. 



GREAT BLACK-BACKED GULL. 



LaRUS MARINUS L. 



Chars. General plumage white, primaries crossed with black ; feet 

 flesh-colored ; bill yellow with red spot. Mantle blackish slate- 

 color ; first primary with the end white for two or three inches ; 

 second primary with a white subapical spot, and, like the 

 remaining ones that are crossed with black, having the tip white 

 (when not quite mature, the first with small white tip and sub- 

 apical spot, the second with white tip alone). In winter, head 

 and neck streaked with dusky. Young : whitish, variously 

 washed, mottled and patched with brown or dusky ; quills and 

 tail black, with or without white tips; bill black. Very large; 

 equalling or even exceeding L. glauais. 



Unlike the preceding, this is a common winter 

 resident along the coast, and some individuals breed in 

 Maine. The great birds may be seen now and then 

 sailing over our harbors in company with Herring and 

 Ring-billed Gulls, from which they are readily dis- 

 tinguished by their superior size, even should they 

 be in the dark plumage of the young birds, as is most 

 frequently the case, or if the slaty mantle of the adults 

 be not visible in flight. They are more numerous on 

 the open coast than in the harbors. 



