Came back from a day out, and checked 'the beach' just by the Hilton Hotel in Rotherhithe early evening. There was a nice 3rd-summer Yellow-legged Gull amongst the usuals, while the first local juvenile Lesser Black-backed were around too. Rotherhithe must be one of the best places to get decent views of Yellow-legged Gulls in Britain and it's surprising nobody else has decided to come down to have a look. Ever.
The following shots illustrate the active primary moult of this individual - the outer primaries (P7 to P10) are old retained feathers, while the new inner primaries are grey in colour (P1 and P2 are grown, P3 half grown and P4 can just be seen coming through) with P5 and P6 fully dropped. The old P10 shows a small mirror while there also seems to be active moult within the tail feathers (that retain some dark blotching). Some nice info on Yellow-legged Gulls here, especially when it comes to ageing.