It's been there since at least 21st and looks like it might hybridise with a f mallard (that happened at Shell many years ago).
Geoff Hargreaves said
Wed May 2 9:08 PM, 2007
a male pintail was found along with some mallard close to canal banking near the benches at 19.00 it,s still got it,s winter plumage and was close enough for conventional photo, for i d checkin
cheers geoff