Birding Alaska

Adult Slaty-backed Gulls Larus schistisagus, Russian Bering sea near Cape Navarin, 1 August 2009.

Three shots of an adult Slaty-backed Gull in flight, Bering Sea near St. Paul Island, 1 May 2009.

Adult Slaty-backed Gull, Russian Bering Sea, 29 August 2009.

This bird is probably a female because of it’s slighter build and relatively small bill.  Compare with the next photo.

Slaty-backed Gull (perched) and Vega Herring Gull Larus argentatus vegae, Bering Sea near St. Paul Island, 26 July 2009.

Slaty-backed Gull, Black-legged Kittiwake Rissa trydactyla, and Vega Herring Gull, Bering Sea, 31 July 2009.

Slaty-backed Gull, Bering Sea, 31 July, 2oo9.

Two Vega Herring Gulls and two Slaty-backed Gulls, Bering Sea, 28 July 2009.

A nice line-up comparing the mantle color of Vega Herring Gull and Slaty-backed Gulls.  Although Vega Gulls can appear to be quite dark, note the greater contrast between mantle and primaries.  On the two Slaty-backed Gulls (right most and second to left) there is much less contrast between the primaries and the mantle.  Lone Vega Gulls, especially when seen on light backgrounds such as snow or ice, are commonly misidentified as Slaty-backed Gulls.  In this these situations the contrast between primaries and mantle feathers are one of the best features.  Note the size difference of the two Vega Herring Gulls; the left most bird is probably a male and the second from the right a female.