The Common Gull from yesterday ... why it was nothing other than L.c.canus

Following seeing and phonescoping this gull yesterday I asked the opinion of Jamie Partridge, Steve Clifton and Derek Charles ...

Interestingly they had all seen similarly dark mantled Common Gulls but more interestingly they had not concluded that any of these had been anything other than the ssp canus ( European Common Gull ).

The 2016 paper in Dutch Birding -Identification of the Larus canus complex by Peter Adriaens and Chris Gibbins highlights some important points -

- the mantle colour of L.c.heinei ( Russian Common Gull ) is not necessarily any darker than that of L.c.c.

- the pale iris colour occurs in 20% of heinei - so a dark iris is not a deal breaker for that

Yesterday's gull showed a number of features pointing to canus -

- bare parts pale coloured                        heinei has bright yellow

- head streaking                                       heinei is white headed with a streaked boa

- p4 without black spots                          heinei has black spots on p4

in addition the white mirrors on p9 andp10 would be smaller on heinei which would also have a complete black band on p5 rather than just a single spot as this bird shows.

Many thanks to Jamie, Steve and Derek for pitching in with this interesting bird.