Lesser Black-backed Gull

Description:

The large Gulls in this area have undergone many revisions over the years. If we go back far enough we find that they were all sub-species of Herring Gull until the Lesser Black-backed was split away when this and the Herring Gull each had numerous sub-species, several of which got swapped about between the two. Now some of these sub-species have been elevated to full species based on latest knowledge and even now arguments still continue between experts as to which ones belong where.
In winter when they moult they all look alike and even many experts agree that it is often impossible to be 100% certain. Some of the differences are on the wing primaries which they lose during the moult and the new ones take a while to grow to their full length. The shade of grey is extremely variable on all species so not a reliable indicator and leg colour is also variable, some young gulls changing from pink to yellow within a couple of years while others can stay pink until they are adults at 4-5 years. Most Herring Gulls legs stay pink throughout their life while others do get yellow legs.
In addition to all this the different species will readily interbreed just to add to the confusion
The result of all this is that any identification of these gulls during Autumn can be taken with a pinch of salt. Come winter a good view of the wing tip primaries should be sufficient to separate them.
For this area Lesser Black-backed Gull and Yellow-legged Gull are the two most common species of large Gull, though Herring Gull and Caspian Gull cannot be ruled out.

Habitat:

Tidal river