Bonaparte's Gull on the Delaware River in album birds

In Albums: nature birds

Apr 27th, 2011, by Alex Zorach

This photo of a Bonaparte's gull, taken on the Delaware river, in Delaware City, DE, shows the upperside of one wing, which has a bold, dark M-pattern (the "M" is formed when looking at the two wings together). This pattern is one field mark that can be used to help identify this species from the smaller little gull or larger black-headed gull. The little gull has a much thicker dark pattern, whereas the black-headed gull has a much less bold pattern, contrasting with darker inner primaries. On this bird, notice only a narrow dark edge to the wing.