The Calidris pugnax, commonly known as the Ruff, is native to Europe, Asia, and parts of Africa. It is primarily found in the northern temperate regions of these continents, with a breeding range extending from northern Europe to Siberia and wintering areas primarily in sub-Saharan Africa, the Indian subcontinent, and Southeast Asia.

The Ruff typically inhabits wetlands, marshes, and muddy coastlines. During the breeding season, it favors grassy or sedge-covered tundra and wet meadows. In winter, it can be found in a variety of wetland habitats, including estuaries, tidal mudflats, rice fields, and freshwater marshes. The environment is characterized by its availability of shallow water bodies and rich muddy areas which provide an abundance of food.

Ruffs are wading birds that feed primarily on invertebrates found in muddy or wetland areas. They have a flexible diet that can include insects, crustaceans, and small aquatic organisms, adapting based on seasonal availability. During the breeding season, males perform elaborate displays to attract females, often in open spaces within their wetland habitats, which emphasizes the importance of low vegetation and open water for breeding success.