Western Marsh Harrier
Circus aeruginosus
- Least concern
- Card rarity: Common
- Birds

The western marsh harrier is a large harrier, a bird of prey from temperate and subtropical western Eurasia and adjacent Africa. It is also known as the Eurasian marsh harrier. Formerly, a number of relatives were included in C. aeruginosus, which was then known as "marsh harrier". The related taxa are now generally considered to be separate species: the eastern marsh harrier, the Papuan harrier of eastern Asia and the Wallacea, the swamp harrier of Australasia and the Madagascar marsh harrier of the western Indian Ocean islands.
Classification
- Class
- Aves
- Order
- Accipitriformes
- Family
- Accipitridae
- Genus
- Circus