Slaty-backed Gull on the Niagara River

This adult Slaty-backed Gull in winter plumage was discovered on 1 January 2017 by Chris Kundle at Goat Island, Niagara Falls NY. Since then it has been seen several times at Thorold on the Welland Canal in Ontario, where Ryan Griffiths found it. It has a huge tertial crescent, mantle shade darker than Lesser Black-backed but not as dark as Great Black-backed. Head streaking and dark that coalesces around pale eye. Its bill is palish at the base with bright red spot on lower mandible. Pink legs were mostly in the water. Goat Island NY on 15 January 2017. Thanks to Willie D'Anna and Betsy Potter and the friends who texted to let us know it was there.

Video of Slaty-backed Gull preening

Head streaking and dark that coalesces around pale eye. Its bill is palish at the base with bright red spot on lower mandible. Pink legs were mostly in the water. Goat Island NY on 15 January 2017.

At 12:30 p.m. after preening, it raised its wings and flew away.

It slept a lot, giving a good profile view of its tertial crescent, scapular crescent and primaries with large white spots (primary tips).

This photo was taken at 3:30 p.m. from the barge viewing area on the Canadian side. The Slaty-backed Gull was roosting among the rocks in the river downriver from the Barge and small islands. 15 January 2016.