The northern harrier (Circus hudsonius) is a bird of prey. It breeds throughout the northern parts of the northern hemisphere in Canada and the northernmost USA.
The northern harrier migrates to more southerly areas in winter with breeding birds in more northerly areas moving to the southernmost USA, Mexico, and Central America. In milder regions in the southern US, they may be present all year, but the higher ground is largely deserted in winter. This bird inhabits prairies, open areas, and marshes.
The northern harrier was formerly considered to be a subspecies of the Eurasian hen harrier.