Breeding and roost sites include rocky habitat along coast, bays, inlets, estuaries, rapids, coves, harbors, lagoons (Campbell et al. 1990). Nesting colonies occur on cliffs of forested, grassy and rocky islands, ledges, sea caves, driftwood logs, pilings, and manmade structures (Gabrielson and Lincoln 1959, Hobson and Wilson 1985, Campbell et al. 1990). Diurnal roosts sandbars, rocky islands, cliffs, logs, and pilings (Godfrey 1986).
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.
Gabrielson, I. N. and F. C. Lincoln. 1959. The Birds of Alaska. The Stackpole Company, Harrisburg, PA and Wildl. Manage. Inst., Washington, D.C. 922 pp.
Godfrey, W. E. 1986. The Birds of Canada. Revised edition. National Museum of Natural Sciences, Ottawa, Canada. 595 pp.
Hobson, K. A. and D. Wilson. 1985. Colony establishment on man-made structures in southwest coastal British Columbia. Murrelet 66: 84-86.