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
White-rumped Sandpiper
Calidris fuscicollis
The white-rumped sandpiper is a relatively small bird measuring only 15–18 cm (5.9–7.1 in), with a wingspan of 36–38 cm (14–15 in). The top of its body is a dull grey-brown colour and it has a white eye stripe. Its beak is of medium length, thin and dark, and its legs are very dark. This bird is often mistaken with many similar-looking sandpipers that live in its range or along its migration path. The plumage is much less distinct during the winter; however, during all seasons males and females remain similar in their appearance. Voice: One of the white-rumped sandpiper vocalizations consists of a repeating "pip, pip, pip …" Their call has a distinctive metallic "tzeep" note which makes them easily identifiable among a flock of shorebirds. It resembles the sound of two pebbles scraping against one another.
ID text from Wikipedia, CC BY-SA 4.0
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