The Northern Harrier is distinctive from a long distance away: a slim, long-tailed hawk gliding low over a marsh or grassland, holding its wings in a V-shape and sporting a white patch at the base of its tail. Up close it has an owlish face that helps it hear mice and voles beneath the vegetation. Each gray-and-white male may mate with several females, which are larger and brown. These unusual raptors have a broad distribution across North America.
Northern Harriers are the most owl-like of hawks (though they’re not related to owls). They rely on hearing as well as vision to capture prey. The disk-shaped face looks and functions much like an owl’s, with stiff facial feathers helping to direct sound to the ears.
Information from the All About Birds website, , © Cornell Lab of Ornithology.