Green Sandpiper
Tringa ochropus

Green Sandpipiers are mainly Winter visitors to the UK, but can be seen from July onwards. They are closely related to the Common Sandpiper and can be differentiated by the lack of prominent white supercillium ('eyebrow') and the lack of the white 'curl' from the breast up the side of the wings.
 

1: Hanningfield Reservoir, 17/09/2006.