16 Birds of Colorado 
Western Gull. Larus occidentalis. 
A.O.U. Checklist no 49—Colorado Record—Cooke 97, p. 50. 
Description.—Adult—Mantle dark slaty; primaries, including the 
inner webs of the first, second and usually the third, black tipped with 
white ; rest of the plumage white ; eyelid vermilion ; bill chrome-yellow 
with a vermilion spot at the angle ; feet flesh-coloured. Length 24; 
wing 16°5; culmen 2°30; tarsus 2°75. 
In winter adults have the top of the head and back of the neck 
streaked with dusky. Young birds are brownish-slaty above, varied 
with buff and whitish; quills and tail-feathers dull black, usually 
tipped with white ; under-parts brownish-grey, speckled with whitish ; 
bill black. 
Distribution.—The Pacific coast, breeding from British Columbia 
to Lower California, occasionally wandering inland. Its inclusion 
in the Colorada avifauna rests on the statement of Professor Wm. 
Osburn, who informed Cooke he took anti example at Loveland, 
September 30th, 1889. 
Herring-Gull. Larus argentatus. 
A.O.U. Checklist no 51—Colorado Records—H. G. Smith 86, 
p. 285 ; Morrison 89, p. 147; Cooke 97, p. 50; Felger 09, p. 277. 
Description.—Closely resembling the Western Gull, but with a less 
robust bill and lighter, paler blue mantle ; the outer primary is black, 
becoming slaty towards the base, and has a white tip and subapical 
white spot on both inner and outer webs, as « rule; the other quills 
are usually without the subapical spot, but have the white tip ; iris 
silvery to pale yellow, bill bright yellow with a vermilion spot on the 
mandible, legs flesh-colour. Length 24; wing 17:18; culmen 2°40; 
tarsus 2°75. 
In winter the head and neck are streaked with dusky and the bill 
is duller. Young birds are mottled with dusky above and below; 
the wing and tail-feathers are dusky blackish, narrowly edged at the 
tips with white ; iris brown, bill dusky blackish, flesh-coloured towards 
the base. 
Disribution.—The Northern Hemisphere generally; in America 
breeding from Minnesota, the Great Lakes and Maine, north to 
Labrador, Hudson Bay and perhaps Alaska ; in winter south to Cuba 
and on the Pacific coast to Lower California. 
The Herring-Gull is only a straggler in Colorado ; a young bird shot 
on @ lake near Denver, November 17th, 1883, is said by H. G. Smith 
to be preserved in, the collection of A. W. Anthony ; Breninger informed 
Cooke that he had observed it near Fort Collins. There is a young 
