The Baird's Sandpiper, Calidris bairdii is a small shorebird. It is among those calidrids sometimes separated in Erolia.

Adults have black legs and a short 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 gray 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. Only the White-rumped Sandpiper also shows this, and that bird can be distinguished by the feature from which it gets its name.

Their breeding habitat is the northern tundra from eastern Siberia to western Greenland. They nest on the ground, usually in dry locations with low vegetation.

They are a long distance migrant, wintering in South America. This species is a rare vagrant to western Europe.

These birds forage by moving about mudflats, picking up food by sight. They mainly eat insects, also some small crustaceans.

This bird was named after Spencer Fullerton Baird, an 19th century naturalist.

Baird's Sandpiper might have hybridized with the Buff-breasted Sandpiper.