The Bonaparte Gull 
No. 280 
Bonaparte’s Gull 
A. O. U. No. 60. Chroicocephalus Philadelphia (Ord). 
Synonyms.— Sea Pigeon. Bonaparte’s Rosy Gull. 
Description. — Adult in summer: Head including throat blackish slate, mantle 
pearl-gray; primaries extensively white, the first six with black terminal portions, the 
third to sixth, in addition, narrowly tipped with white; the first quill with outer web 
and tip black, the second and third altogether white with black tips, the fourth white 
on outer web, pearl-gray on inner web, with touch of white at extremity of terminal 
black, effecting the transition to the nearly uniform basal pearl-gray of inner primaries; 
remaining plumage pure white, the underparts more or less flushed with pale rosy. 
Bill jet black; feet and legs rich orange-red, with black nails; feathering of eyelids 
white posteriorly, the skin carmine. Adult in winter: Without the black hood; a dab 
of slate behind the ear and another before the eye, with a plumbeous suffusion of occiput 
instead; rosy tint of underparts wanting; bill lighter basally, and feet pale flesh-color. 
Immature: Like adult in winter, but plumbeous suffusion of hind-head more extensive 
and tinged with brownish; the pearl-gray of mantle less distinct and varied by brownish 
gray; lesser wing-coverts and inner tertials mostly brownish gray; primaries mostly 
blackish on exposed outer webs, where the adult is white, and white on outer webs of 
inner primaries, where adult is pearl-gray; the inner primaries narrowly tipped with 
white as before; tail crossed terminally, or nearly so, with a broad band of blackish 
or brownish dusky; bill still lighter, but blackish toward tip. First plumage: Much as 
in immature, but crown, cervix, sides of neck and back, plumbeous dusky varied by 
brownish gray; feet still lighter. Length of adult: 304.8-355.6 (12.00-14.00); av. of 
10 Monterey and Alaskan specimens: wing 268 (10.55); tail 101.2 (3.98); bill 28.4 
(1.12); depth at angle 6.6 (.26); tarsus 35.3 (1.39). 
Recognition Marks. —Little hawk size; with Sabine’s, smallest of local gulls; 
size of Common Tern ( Sterna hirundo ); head black in breeding plumage; bill black or 
mostly black; mantle gull-blue; primaries mostly white and gull-blue, tipped with 
black and very narrowly with white. To be told at a glance from the terns by its 
shorter, squarish tail, and in breeding plumage by head being black all around. For 
comparison with Xema sabini see under next species. 
Nesting. —Does not breed in California. Nest: Of sticks, lined with grass, 
etc.; placed four to twenty feet high in bushes, trees, or on stumps, or in default of such 
upon high ground in marsh. Eggs: 3; rarely 4; olive-gray, greenish olive-gray, or 
brown, with smallish spots or blotches of umber and violet-gray, chiefly about larger 
end. Av. size 48.3 x 33 (1.90 x 1.30). 
General Range. —North America. Breeds from northern British Columbia, 
north in Alaska, Yukon, and northern Mackenzie. South in migrations over practi¬ 
cally the entire continent to the southern states, Lower California, and northern Mexico. 
Winters north to South Carolina, and sparingly to Washington. 
Distribution in California. —Abundant during migration along the seacoast, 
and casually throughout the interior. Winters commonly along the coast north to 
Monterey and more sparingly northward in suitable harbors. 
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