60 



KEY TO GULLS (Cont.) 



54' Primaries dark brown with conspicuous pale edgings; underside of 



primaries pale brown; eye brown. THAYER'S GULL, second year 



55 Tail nearly all dark. YELLOW-FOOTED WESTERN GULL, second year 

 55' Tail mostly white, with dark spots on all or some tail feathers. 56 



56 Outer three primaries not distinctly darker than inner primaries and 

 secondaries; bill with prominent gonydeal angle (Plate 26a-2). 



WESTERN GULL, third year 



56' Outer three primaries distinctly darker than inner primaries and 



secondaries; gonydeal angle not as prominent (Plate 26b). 57 



57 Legs bluish-gray to greenish; iris dark brown. 



CALIFORNIA GULL, third year 



57' Legs bright pink; iris yellow or brownish. 58 



58 Iris clear yellow; under surface of primary tips black. 



HERRING GULL, third year 



58' Iris brown, often flecked with dark brown; under surface of primary 



tips pale gray. THAYER'S GULL, third year 



59 Bill red with black tip; mantle and adjacent wing surface dark 

 slate-gray; tail black, tipped with white. 



HEERMANN'S GULL, adult 



59' Bill pale pink at base with black tip; mantle and adjacent wing 

 surfaces dark gray washed with brown OR these areas dark brown; 

 tail dark blackish-brown, lacking white tip. 60 



60 Mantle is pure dark gray; adjacent wing surfaces with some 

 dark brown; head and underparts medium gray. 



HEERMANN'S GULL, second year 



60' Plumage wholly dark chocolate brown, somewhat paler on upper wing 



surface. HEERMANN'S GULL, first year 



