Slaty-backed Gull

Wellfleet, Massachusetts - 22 January 2012

Blair Nikula

The images below depict an adult Slaty-backed Gull (Larus schistasagus) present in a high tide gull roost at Wellfleet Harbor, MA, on 22 January 2012. Salient features evident in these photos include the slate-gray mantle with a very broad, white tertial "skirt"; stocky build; heavy streaking on the hind neck and around the eye; straight, pale yellow bill with very little gonydeal angle; and relatively short, bright pink legs.

Not visible in these photos is the distinctive primary pattern: the outermost primaries (P7-P10) were black distally, with a long white mirror and thin black subterminal band on P10, and a shorter white mirror on P9; and conspicuous white tongue tips were present on P5-P7.
However, Jeremiah Trimble got additional photos, including a couple of spread-winged shots showing this distinctive primary pattern, which are posted here.

All images were taken with a Canon 7D and a 100-400 IS lens and are copyright 2012, Blair Nikula.

In the shot below, the very heavy streaking on the hind neck is prominent.