Which harrier is known as the marsh hawk?

The Northern Harrier is commonly referred to as the marsh hawk due to its preference for marshy and open grassland habitats where it hunts. This bird is distinctive not only for its hunting proficiency but also for its unique physical characteristics, such as a long tail and a distinctive facial disc, which help it in locating prey. The term "marsh hawk" reflects its habitat and hunting behavior, as it often flies low over the ground, gliding silently in search of small mammals and birds, particularly in wetlands and marsh areas.

In comparison to the other harrier species, the Northern Harrier is the one most closely associated with marsh environments, which is why it is commonly called the marsh hawk. The Southern, Eastern, and Western Harriers, while they may inhabit various regions, do not share the same association with marshy regions, which makes the Northern Harrier the correct answer in this context.