Here are two seemingly identical waders flying together. They are quite cold in colour, almost black and white in appearance, and the wings are dark (apart from a very thin leading edge to the primaries). The long, slightly upturned bill hints that we are dealing with a Tringa sandpiper. The lack of wing-bar immediately rules out birds such as Redshank. The white rump flowing into extensive white in the centre of the back rules out Green and Wood Sandpipers and the American yellowlegs (which have small, square white rumps). That grey-based bill and the long greenish legs, with feet projecting beyond the tail rule out Spotted Redshank and the longer-billed Bar-tailed Godwit, and should take you to these being Greenshanks.
KEY FEATURES Plain dark wings lack any wing-bars Extensive white back from barred tail almost to nape Grey-based, black-tipped slightly upturned long, robust bill Greeny-yellow feet project beyond tail Rich buff tones to plumage