Adult Thayer's Gull at Oshawa Harbour

This adult Thayer's Gull in winter plumage was on the beach at Oshawa Harbour on 25 January 2016. Its identification is based on a combination of 5 characters: (1) It has blackish wingtips approaching the black of Herring Gull, (2) with large white primary spots that are not enclosed by black as in Herring Gull, (3) the eye is dark, (4) the legs are a deep pink, (5) and the mantle shade is similar to Herring Gull. The head streaking is also typical of Thayer's in winter.

Thayer's Gull open wing. Not having a dark bar on P5 is normal. There is a very small spot on P5.

This is a dark-eyed Thayer's. Note: eye colour in Thayer's Gulls is variable from light to heavily speckled, but rarely is it as pale as the lemon yellow of Herring Gulls.

Thayer's Gull (back) with adult Herring Gulls showing very similar mantle shade. 25 January 2016. Any differences could be caused by light and angle.

Link to: Four Kumlien's Gulls and their eyes at Oshawa Harbour, Ontario, 25 Jan 2016