Nests on rocky coastlines; forages in near-shore waters.Back to top
Fish, crustaceans, and marine invertebrates.Back to top
Nest may consist of shells, pebbles, seaweed, and bones, or egg may be laid directly on rock with no nest material at all. Placed on rocky coast, often under overhang or boulder, or in a cavity.
|Clutch Size:||1-2 eggs|
|Egg Description:||Dull white to pale green, boldly marked with dark spots and blotches.|
|Condition at Hatching:||Covered with black down and can move about on land.|
In courtship display, male stands upright, points bill down, and walks around female with exaggerated steps.Shows various lunges, turns of the head, and other posturing in territorial interaction with other Black Guillemots.Dives under water to capture prey, using its wings to swim. Small prey swallowed under water; larger items brought to surface.Back to top
Lack of accurate census data makes determination of population trends difficult. The North American Waterbird Conservation Plan estimates a North American population of 100,000-200,000 breeding birds, and this species rates a 9 out of 20 on the Continental Concern Score. They are listed as a Species of Lowest Concern, and are not on the 2014 State of the Birds Watch List. The Black Guillemot is more susceptible to ingestion and biomagnification of marine pollution than other alcids because it takes prey from shallow water or at the sea floor. Studies have shown accumulation of mercury, pesticides, and crude oil residues in body tissues and eggs. Oiling of feathers from spills at sea usually results in death. Global warming may also affect populations.Back to top
Butler, Ronald G. and Daniel E. Buckley. 2002. Black Guillemot (Cepphus grylle), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.
Kushlan, J. A., M. J. Steinkamp, K. C. Parsons, J. Capp, M. A. Cruz, M. Coulter, I. Davidson, L. Dickson, N. Edelson, R. Elliott, R. M. Erwin, S. Hatch, S. Kress, R. Milko, S. Miller, K. Mills, R. Paul, R. Phillips, J. E. Saliva, W. Sydeman, J. Trapp, J. Wheeler and K. Wohl (2002). Waterbird conservation for the Americas: The North American waterbird conservation plan, version 1. Washington, DC, USA.
Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.
North American Bird Conservation Initiative. 2014. The State of the Birds 2014 Report. US Department of Interior, Washington, DC, USA.
Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.