Baird's Sandpiper
Calidris bairdii
Adults have black legs and a short, straight, thin dark bill. They are dark brown on top and mainly white underneath with a black patch on the rump. The head and breast are light brown with dark streaks. In winter plumage, this species is paler brownish grey above. This bird can be difficult to distinguish from other similar tiny shorebirds; these are known collectively as "peeps" or "stints". One of the best identification features is the long wings, which extend beyond the tail when the bird is on the ground.
ID text from Wikipedia, CC BY-SA 4.0
Stilt Sandpiper
Calidris himantopus
The stilt sandpiper resembles the curlew sandpiper in its long bill, long neck, pale supercilium and white rump. It is readily distinguished from that species by its straighter bill (only slightly curved, not obviously so), its longer and greenish-yellow (not black) legs, and in flight, by the lack of a wingbar. It also lacks an obvious wing bar in flight. Breeding adults are distinctive, heavily barred with blackish bars on a white background beneath, and with reddish-orange patches above and below the white supercilium. The back is brown with darker feather centres.
ID text from Wikipedia, CC BY-SA 4.0
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