- 11–15 in
- 29.9–31.5 in
- 6.3–7.9 oz
- Mouette de Bonaparte (French)
- Gaviota de Bonaparte (Spanish)
- The Bonaparte's Gull is the only gull that regularly nests in trees.
- The English name of the Bonaparte's Gull honors Charles Lucien Bonaparte, who made important contributions to American ornithology while an active member of the Academy of Natural Sciences of Philadelphia during the 1820s. The scientific name philadelphia was given in 1815 by the describer of the species, George Ord of Philadelphia, presumably because he collected his specimen there.
- During the breeding season, the Bonaparte's Gull feeds mainly on insects, often catching them on the wing.
Breeds around lakes and marshes in boreal forest. Winters along lakes, rivers, marshes, bays, and beaches along coasts.
Small fish and large invertebrates, including insects. Does not eat garbage or carrion.
- Clutch Size
- 1–4 eggs
- Egg Description
- Buffy green, with dark spots and blotches.
- Condition at Hatching
- Semiprecocial with eyes open. Covered in down. Able to stand within a day, but usually remain quiet in nest for a week.
Open cup of twigs, small branches, and bark, lined with mosses and lichens. Placed in tree or bent-over rushes.
Flies along and plucks food from surface of water, or plunges into water to pick food from water.
Numbers of Bonaparte's Gull have increased over last 100 years. It is difficult to get estimates of population size, but the Waterbird Conservation for the Americas estimates that the species rates at least an 8 out of 20 on the Continental Concern Score and lists it as a Species of Moderate Concern. They are not on the 2014 State of the Birds Watch List.
- Burger, J., and M. Gochfeld. 2002. Bonaparte's Gull (Larus philadelphia). In The Birds of North America, No. 634 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.
- North American Bird Conservation Initiative, U.S. Committee. 2014. State of the Birds 2014 Report. U.S. Department of Interior, Washington, DC.
- Waterbird Conservation for the Americas, Technical Services Committee, Waterbird Conservation Council. 2006. Status Assessment Spreadsheet - Factor Scores and Categories of Concern for Colonial Waterbirds.