Another effective hunting strategy is dropping down on prey from a high perch. Migration is mainly along the coasts and the Great Lakes. The tundra birds move as far south as Central Argentina and Chile during the boreal winter. Some even spend the winter in the Amazon basin at Manaus, Brazil. In the first year, dispersal is greatest with females ranging further than males.
Adult males tend to have greater site fidelity than females.
Pairs often remain together. The nest is little more than a small round scrape in the accumulated debris on a ledge of a cliff or a tall building. Old stick nests of other raptors are also used, as well as the hollows of broken trees. These are usually 50 to 200 feet above the ground. Both parents incubate the 3-4 creamy or buff eggs, with red and brown markings, for 28 to 29 days.