The Western Marsh Harrier (Circus aeruginosus), is native to a wide distribution across Europe, parts of Asia, and northern Africa. It is predominantly found from the British Isles and Western Europe, across to Russia and Central Asia, with northern populations migrating south to Africa and the Indian Subcontinent for the winter.

The Western Marsh Harrier typically inhabits wetlands, including marshes and reed beds, which provide both food resources and nesting sites. They prefer environments with extensive reed beds, fresh or brackish water bodies, and open wetlands, but can sometimes be found in drier habitats like agricultural areas.

The Western Marsh Harrier occupies an ecological niche as a diurnal bird of prey, feeding primarily on small mammals, birds, and aquatic creatures. It plays a critical role in its ecosystem by helping control the populations of these prey species. During the breeding season, they build large nests of reeds and earth, often in dense reed beds, providing a stable and concealed environment for rearing young.