Nick Bonomo and I spent thirty minutes on this pale first-cycle bird and came away without drawing any firm conclusions. Of course, an hybrid of some kind was very much in our thoughts - but what would be the parentage?
We thought that size, structure and bill size comfortably ruled out Kumlien's but what about a pale-end Thayer's Gull? In the Eastern US we're looking for mostly classic medium-dark examples of Thayer's but many web images show examples paler than the birds we detect, especially birds photographed from mid-January onwards.
As always, any thoughts/help would be much appreciated.
Pic attached plus about 15 images at the link above.