Open marshland and meadows. Banding results have shown several to be over 16 years of age.
Adult males have blue-gray upperparts and white underparts.
The females are brown above and buffy below, with brown streaking down the sides of the chest and flanks. Juvenile harriers of both sexes have dark brown backs with rusty overtones and cinnamon underparts, with no streaking. The northern harrier occurs throughout the United States, Canada and north to Alaska. They are also found in Europe and Asia. The species winters over parts of its nesting range, but more commonly south through Mexico, Central America, northwestern South America and the West Indies.