The breeding biology of the genus Cepphus (Alcidae) is represented in the literature for two of the three species: Cepphus grylle, the Black Guillemot, and Cepphus columba, the Pigeon Guillemot (Asbirk 1978, 1979a and b; Cairns 1978, 1979, 1980, 1981; Drent 1965; Hyde 1936, 1937; Preston 1968; Storer 1952; Thoresen and Booth 1958; Winn 1950). Notations within larger compilations (Dement'ev and Gladkov 1951; Kozlova 1957) and a short paper by Nazarov and Labzyuk (1972) have been the only reports published on the habits of Cepphus carbo, the Sooty (or Spectacled) Guillemot.