Summer Range: Northern Harriers’ breeding range spans North America from Alaska to Newfoundland, and south to North Carolina. Adults arrive on the breeding grounds at any time from February to early June, with males preceding females by days or weeks.
Winter Range: Migrating Harriers travel singly or in small groups, and prefer to follow coastlines in their migration patterns to take advantage of strong thermal air currents. Harriers that breed in the northern United States tend to fan out across the southern two-thirds of the country, while Harriers from arctic breeding ranges fly farther south, many to Central America, Venezuela and Colombia. A few Harriers may remain on the northern breeding range through the winter, as long as snow cover doesn’t interfere with their hunting success.