Franklin's Gull (Leucophaeus pipixcan)
Bonaparte's Gull (Chroicocephalus philadelphia)
Black-headed Gull (Chroicocephalus ridibundus)
09 December 2020. Stockton, California.
Gull Trifecta
Gull trifecta.

Black-headed Gull (Chroicocephalus ridibundus)
on right is a rarity in North America, California has 32 previous Black-headed Gull records. Immatures and adults in winter plumage lack the dark brown hood. They are distinguished from the similar Bonaparte's Gull by their larger size, thicker orange based bill, and darker underwings as seen here. Note also the dark "comma" on the outer primary coverts, unique to this species. This first cycle bird was found by David Yee on 04 December. It has been associating with hundreds of Bonaparte's Gulls at the water treatment plant.

Franklin's Gull (Leucophaeus pipixcan) on left is a rare but regular migrant and winter visitor in California, this is an immature (first cycle) showing dark tail band. These gulls are long-distance migrants, breeding in the interior of the North American prairies and wintering primarily along the west coast of South America. This species is unusual in that it has two complete molts each year. Here
the the new adult white tipped inner primaries contrast with older black tipped juvenile primaries.


Bonaparte's Gull (Chroicocephalus philadelphia) in the middle is the smallest of the regularly occurring gulls in our area. They are migrants and winter visitors from breeding grounds in the boreal forests of Alaska and Canada. Their name honors Charles Lucien Bonaparte, a cousin of Napoleon.

Canon SX70 HS.
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