It's starting to get confusing now, if it wasn't already! Two weeks ago I
reported on a hybrid pairing of Mediterranean gull (thought to be the male)
and black-headed gull on the Mere at Martin Mere. I said at the time that the
Med gull was a 3rd calendar year bird because it had black markings on the
primary tips. I also said that I'd never seen the resultant offspring of a
hybrid pair so was looking forward to seeing the young of this pair. Wrong on
both accounts it seems! The bird facing left with the black hood is not only a hybrid Med x black-headed gull, it's also not 3cy, I think it's an adult.
The first clue is in the photo above and I really should have noticed it the
first time that I saw the bird. The bill is too slim, the wrong shape and the
wrong colour for adult or near adult Med gull. Then there's the hood - I
realise that this can be variable depending on how the bird is behaving, but the hood clearly does not extend as far down the nape as a typical Mediterranean
gull. And there are plenty of the latter about for comparison, at least 10
adults at Martin Mere at the moment, including a pure pair on the next island
to this. They're like chalk and cheese!
Finally there is the wing pattern. It's almost adult black-headed gull, with
the pale outer primaries. Far from being a 3cy Mediterranean gull, I think
that this is actually an adult Med x black-headed gull hybrid. As it's now
paired with an adult black-headed gull, the resultant offspring will be 2nd
generation hybrids. That should be interesting....
Thanks to Graham Clarkson for pointing this out to me and Ian McKerchar for
feedback on my photos.
Here's the probable female black-headed gull on the nest.
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