BIRD NOTES AFIELD 



There is one species, however, so entirely distinct from the 

 others that it can be known at a glance — Heermann's gull, a 

 form confined to the Pacific Coast. It is of medium size, with 

 a dark-slaty or plumbeous back, a dusky-gray breast and black 

 wings and tail, the latter narrowly tipped with white. The 

 head is white and the bill vermilion in the breeding bird, but 

 in the immature plumage the white is replaced by mottling, 

 and the bright hue of the beak by brownish black. 



Having familiarized ourselves with this very dark and 

 wholly unique species, we may roughly classify the remaining 

 ones in three groups according to their size. In all of them the 

 adult bird is mostly white, with a mantle (as the plumage of 

 the back is termed) of pearly bluish or slaty gray, the white 

 of the head becoming mottled in winter-time. The immature 

 birds are dusky grayish or brownish, more or less mottled above 

 and below. It is necessary to understand that the distinctions 

 between the species are very subtle in character, and that the 

 best we can hope for with the live bird flying about us, is to 

 approximate its name. With the young, even this is impos- 

 sible in many instances, as the characteristics are even less 

 defined. 



Of gulls of the largest size, three species are common about 

 the bay — the glaucous-winged, the American herring and the 

 western gull. Hie first of these may be known by the long 

 flight or wing-quills, which are bluish gray in color, save for 

 the white spots at their tips. In the other two species the wing- 

 quills are black or blackish brown, usually marked with large 

 spots of white. The western gull has a much darker, slaty- 

 colored mantle, and a stouter bill than the American herring- 

 gull. This latter species may consequently be known as one 



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