I’ve tried to identify this bird and failed - help!

QCan you help identify this bird seen at Wicken Fen, Cambridgeshire, in early May? I have not been able to identify it using books or the web and would really appreciate some expert advice.

Sean Greenway, Soham, Cambridgeshire

AIt’s a Ruff, which occasionally breeds in the UK in very small numbers, but is more often seen here in winter or on passage. Ruff are wonderfully variable in their plumage, and even in a very large flock it can sometimes be impossible to find two alike. It’s thought that this wide variation is to help recognition of individual birds in a species that is pretty much mute, but which ‘leks’ to find mates. Whatever the plumage, though, the structure of Ruffs is very distinctive, with a small head, long neck, mediumlength bill, and a rather pot-bellied appearance.