Bulloch, David K. 1989. The Wasted Ocean . A Natural and Human History of the Islands of Maine . Down East Books, Camden Maine. Croxall, J.P., ed.
Population changes in New England seabirds.
Drury, W.H. 1974. Population changes in New England seabirds. The Birder's Handbook . Hamlyn Limited, London. Junger, S. 1977.