Various open situations from tundra, moorlands, steppe, and seacoasts, especially where there are suitable nesting cliffs, to mountains, open forested regions, and human population centers (AOU 1983). Often nests on ledge or hole on face of rocky cliff or crag. River banks, tundra mounds, open bogs, large stick nests of other species, tree hollows, and man-made structures (e.g., ledges of city buildings) are used locally (Cade 1982). Nests typically are situated on ledges of vertical rocky cliffs, commonly with a sheltering overhang (Palmer 1988, Campbell et al. 1990). Tundra populations nests typically on rocky cliffs, bluffs, or dirt banks. Ideal locations include undisturbed areas with a wide view, near water, and close to plentiful prey. Substitute man- made sites include tall buildings, bridges, rock quarries, and raised platforms.
AOU. 1983. Check-list of North American birds. 6th ed.American Ornithologists’ Union, Washington D. C.
Cade, T. J. 1982. The falcons of the world. Cornell University Press, Ithaca, NY. 192 pp.
Campbell, R. W., N. K. Dawe, I. McTaggart-Cowan, J. M. Cooper, G. W. Kaiser, and M. C. E. McNall. 1990. The Birds of British Columbia. Vol. 1 and 2, Nonpasserines. UBC Press, Vancouver, B.C.
Palmer, R. S. (ed.). 1988. Handbook of North American Birds. Vol. 4. Diurnal raptors, Part 1. Yale Univ. Press, New Haven, CT. 433 pp.