28 January 2020

A big baffling brute

A couple of weeks ago, I made a quick trip to Alexandra Lake (Wanstead Flats) to try and see a frequently reported 3rd calendar year (2nd winter) Caspian Gull. I failed.

I did get an adult Great Black-backed Gull that flew almost as soon as I saw it. I also saw a classic 2cy Yellow-legged Gull. It was big, with a thick bill, pronounced gonys angle, nice pale head and dark eye mask, nice full brown tertials, and advanced scapular moult. It also flew whilst I was watching it and revealed a nice pale rump which contrasted with a thick, dark tail band. It really did have everything you would want to see - a textbook bird. 

So that was two patch year ticks in amongst a huge number of Commons, Black-heads, Herring, and Lesser blacks (in that declining order of number). 

Then I saw a gull which baffled me. My first thought was that it was another 2cy Yellow-legged Gull (just shows how sometimes you should trust your instincts) as it looked bulky and pale headed. But I slowly began to discount my instincts. It wasn’t just bulky, it was huge! It had a strange pale bill, the head was a bit streakier than you would like to see. It bobbed about on the water and floated right up past a 2cy Herring Gull. It was significantly bigger. I felt the size differential meant it was clearly a 2cy GBBG, took a record shot and left.

Here is that record shot:

The brute behind a 2cy Herring Gull

A week later and I returned to Alex and saw this big 2cy bird again. Something wasn’t quite right. It was very big, but it wasn’t quite as big as you would want for GBBG. There was a smudge where I would have preferred a mask for Yellow-legged Gull, but I couldn’t quite reconcile my thoughts between GBBG or YLG. That was until the bird flew. It revealed a nice white rump and a thick, distinct, dark tail band. I really believe this bird must be at the very upper size limit for the L. michahellis species.

Note eye smudge and that big pale bill, but also the moult of a YLG

Just look at this thick tail band

No, really, have a look


  1. James - several years ago we ringed a bird similar to this at Pitsea. We actually put it down initially as a hybrid believing it to be a possible Herring X GBB. It had the same pale bill as your bird but was a cross between YL and Herring wing pattern, rump and tail band. This bird has been seen a few times now as it was colour ringed and has grown up to be a fairly normal Great Black-backed Gull. I am fairly sure it had something else in it's make up and only DNA would have told us but it has now been re assigned to GBB.

  2. Thanks Paul. Interesting stuff. I’d love to see a pic of that bird some time (if you have one to share via Twitter or email perhaps?)

    Would you agree that this bird in the blog ticks enough boxes that it is almost certainly a YLG or enough of a YLG to record it as one? The more I look at it and pictures of it, the more I struggle to see anything else.

    Thanks, James