Mike Baron digiscoped this interesting-looking large gull at Sidegate Landfill yesterday.
In flight over the tip it bore a strong resemblance to a first-winter Glaucous Gull but upon closer examination, however, it clearly shows features more closely associated with Herring Gull.
Although it may be a Glaucous Gull x Herring Gull hybrid I think it more likely to be a leucistic Herring Gull as its head shape does not seem to fit Glaucous, it doesn’t appear to have Glaucous’s beady eye and, as well as the ghosted subterminal tail band, it has an indistinct secondary bar. It is larger, however, than any of the Herring Gulls present!
It does not show a typical striking Glaucous Gull x Herring Gull hybrid bill pattern, which is often virtually identical to first-winter Glaucous but it is not too far adrift from this. Compared with the Herring Gull in the photos, the primaries and tertials are much paler. A pitfall for the unwary Glaucous Gull seeker!