Gulls. 
Vv 47. Great Black-backed Gull (Larus marinus). L. 
29. Ads., summer. Back and wings slaty black; wing 
feathers tipped with white. Ads., winter. Similar, but. 
head and neck streaked with dusky. Yung. Back 
grayish brown margined with buffy white; rump whiter; 
primaries black; below white more or less marked with 
dusky. Notes. ‘‘A braying ha-ha-ba, a deep keow, keow, 
a short barking note, and a long-drawn groan, very 
loud and decidedly impressive.’’ (Brewster.) 
Range.—North Atlantic and northern Europe; breeds in North 
America from Nova Scotia to Greenland; winters south to Great 
Lakes and South Carolina. 
48. Slaty-backed Gull (Larus schistisagus), L. 26. 
Ads., summer. General appearance of No. 47; back 
lighter; primaries as figured. Ads., winter. Head and 
neck streaked. Yug. Above brown margined with 
buff and white; primaries brown; tail brown with little 
or no mottling; below brown. 
SN 
from Stejneger 
Range.—''North Pacific, chiefly on the Asiatic side; Herald Island, 
Arctic Ocean, and Alaskan coast of Bering Sea.”’ (A. O. U.) 
49. Western Gull (Larus occidentalis). L. 24. Ads., 
summer. Head, neck, tail, and underparts white; back 
slaty gray; outer primaries black, a large white spot 
near tip of first one. Ads., winter. Crown and hind 
neck streaked with brownish. Yug. Grayish brown 
mixed with white; wings and tail fuscous. Notes. 
Ooéék, o0€&h, o0€€k; ca-ca-ca, and other calls. 
Range.—Pacific coast; breeds and winters from Lower California te 
British Columbia. 
57. Heermann Gull (Larus heermaui). L.17. Ads., 
summer. Bill red;head and throat white, shading into slate 
above and below; tail blackish, tipped with white; 
primaries black. Ads., winter. Head and neck streak- 
ed with grayish brown. Yung. Uniform grayish 
rown. 
Range.—Pacific coast of North America; breeds from Mazatlan, 
Mexico, north to Lower California; occurs regularly north to Van- 
couver Island; winters south to Panama. 
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