Calidris

Calidris is a genus of small to medium-sized shorebirds in the family Scolopacidae, commonly known as sandpipers. Members are typically characterized by slender bills and legs, and cryptic plumage that blends with mudflats and beaches. They forage for invertebrates by probing and picking along the water’s edge, often in flocks.

Species of Calidris occur worldwide, with most nesting in Arctic or subarctic regions and wintering in temperate and tropical coasts. They are associated with intertidal flats, mudflats, saltmarshes, and sandy shores, where they feed on crustaceans, mollusks, polychaete worms, and other invertebrates. Many Calidris species undertake long-distance migrations between breeding and wintering grounds, sometimes traveling over oceans.

The genus contains around two dozen species. Notable examples include the Sanderling (Calidris alba), Red Knot (Calidris canutus), Dunlin (Calidris alpina), Curlew Sandpiper (Calidris ferruginea), Purple Sandpiper (Calidris maritima), Western Sandpiper (Calidris mauri), and Baird’s Sandpiper (Calidris bairdii). The exact composition of Calidris varies with taxonomic authority, as some classifications place certain species in other genera such as Erolia.

Behavior and reproduction: Calidris species are typically gregarious outside the breeding season. Breeding is generally ground-nesting on tundra or heath, with a clutch of eggs incubated by one or both parents. Habitat disturbance, wetland loss, and heavy human activity can impact populations, particularly at migratory stopover sites.

Conservation status varies by species and population, but ongoing monitoring of habitats and migratory routes is widely regarded as important for shorebird conservation.