Caspian Gull - Cocker's Dyke, Lancashire - 3rd September 2015

 Having a bit of time off this morning, I thought I'd be productive and learn a bit about Caspian Gulls. Previous to today, I had seen a 2nd winter at Chasewater in December and a moulting 1st Summer/2nd Winter at Ainsdale recently (as you'll probably see below). 2nd calendar year birds really are striking things and I feel fairly comfortable with them. Juveniles really aren't that common yet in the UK (or at least they aren't getting IDd as readily as the older birds).
There has recently been a reliable bird at Cocker's Dyke in north Fylde in Lancs which is a juvenile. I arrived mid-morning at about 08:45, and began searching. It took about 45 minutes before anything other than a Greater Black-back or adult Lesser Black-back appeared in my scope. A group of 5 juvenile gulls appeared which were mainly Lesser Black-backs, but a really pale bird was very striking. Before I could get much on it, it fell asleep making it somewhat more difficult to ID.
It looked good though with really black primaries extending well beyond the tail, black centres to the tertials and clean white tips, faded brown juvenile scapulars and a couple of freshly moulted grey scaps. They were generally fairly clean with a single black line down the centre. The head was generally fairly clean with a slight mask and a streaked shawl to the nape. When it eventually woke up, it had a parallel sided bill, pear-shaped head and a long neck. It walked onto a bit of mud/sand and was incredibly long-legged, 'filled nappy' on the vent which was extremely clean and white.
It took off and revealed 'Venetian blinds' to the inner primaries, black secondary bar contrasting to the pale coverts and a white rump contrasting with the black tail tip. Very educational.