Remsen, J.V. 1978 Black-headed Gull Larus ridibundus Feb.25 includes details seen when we returned late in the [coit] afternoon and watched the bird flying around the slough for 20 minutes, but never closer than 200 yds. Uppervwing leading edge of wing white. This edge in the primaries was not as conspicuous as on Bonaparte's Gull or field guide pictures of Black-headed at least 5 outmost primaries were black-tipped Underwings: wing-tings whitish; test of underwings dusly grayish. This contrast was not always apparent- only in good light at least 5 outermost primaries were black-tipped; These primaries were also darker basally, darker than the rest of the dusly underwing Also, when the bird was sitting on the water, the underside of the outermost primary could be seen when the bird was facing away from me, and it seemed to have a black border characteristic of ridibundus: U