Gulls 



47, Great Black-backed Gull [Larus marinus). L. 

 29. Ads., summer. Back and wings 5il3ty black; wing 

 feathers tipped witli white. ^ds.,iviKUr. Similar, but 

 head and nectc streaked with dusky. Yng. Baclj 

 grayish brown margined with butly white; rump whiter; 

 primaries black; below white more or less marked with 

 dusky. NaU:i. "A hlray]ng ha-ha-ha, a deepk:iow, keow, 

 a Short barking note, : and a long-drawn groan, very 

 loud and decidedly impressive." (Brewster.) 



Range,— North Atlantic and noniiern Europe; breeds In Nor;h 

 America from Nova Scotia to Greenland; winters south to Great 

 Lakes and Soutli Carolina. 



48. Slaty-backed Gull {Lams schistisagus). L. 26, 

 Ads. , bummt-r. General appearance of No. 47; back 

 lighter; primaries as figured. Ads., winter. Head and 

 neck streaked. Yng.. ' Above brown margined with 

 buff and white; primaries brown; tail brown with little 

 or no mutlling; IJielow brown. 



Range, —"North Pacific, chiefly on Ihp Asiatic side; Herata Island. 

 Arctic Ocean, and Alaskan coast of Bering Sea." (A. O. U.) 



49. Western Gull {Lams occidentalis). L. 24. Ads., 

 mmme.r. Head, neck, tail, and underparts white; back 

 slaty gray; outer (irimariee black, a large white spot 

 near tip of Inst one. Ads., wiuUr. Ciown atid hind 

 neck streaked w,th brownish. Yng. Grayish brown 

 mixed with white; wings and tail fuscous. Notes, 

 Oosck, ooeek, ooeek; ca-ca-ca, and other calls. 



Range.— Pacific coast; breeds and winiers from Lower California w 

 British Columbm. 



57. Heermann QaWlLarusheermanni). L. 17. Ads.^ 

 summer, BlU reLl;head and throat white, snading into slate 

 above and below; tail^ blackish, tipped with white; 

 primaries black. Ads.,wiittef. Head and neck streak- 

 ed with grayish brown. 1 ' tg. Uniform grayish 

 brown, 



Range. — Pacific coast of No, th America, breeds from Mazatlan, 

 Mexico, ngrih to Lower California; occurs regularly north to Van- 

 couver Island; winters south to Panama, 



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