I was on the tip on Saturday, rudely interrupted by news of that big brute of a finch. It didn't however dent my enjoyment of the gulls and after seeing a 2nd-winter Caspian Gull (the same bird that has been regular at Wat Tyler CP recently), the other Caspian-esque Gull was this individual, which I firmly believe comes from that hybrid swarm in/near Poland where cachinnans mixes with argentatus Herring Gulls. So for now I'm going to call this near adult (presumably 5cy) bird a hybrid.
Interestingly, to throw even more into the mix, a Polish-ringed bird that was seen as a first-winter several winters ago - where it looked like a decent 1st-winter Caspian Gull - was seen again on the tip as a near adult, where it looked decidedly like a Herring Gull. Interesting stuff, and it leaves one to wonder what all these 1st-winter Casps we see in Britain will actually mature into. The couple of adult Med Gulls whacking about were slightly easier to identify!
Hi Rich, interesting bird - very Caspian-like but for P5. I had missed the importance of CG's comment on iris colour, and will have to re-read the paper as I'm not sure why this would be the case - given that ad Caspian is said sometimes to have a pale iris and large gulls often develop pale irides from their second winter, it's not obvious to me why this would be a problem. For reference I recall pics of a spring ad Caspian Gull with a very pale iris on Steve Arlow's website www.birdersplayground.co.uk - wouldn't such a bird surely have developed its eye 'paleness' quite some time before adulthood? Plenty of food for thought, as always with gulls!
ReplyDeleteWith a bit of luck, one day all these large gulls will have hybridised so much that they converge into one species. That is, of course, the view of a larophobe!
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