Geographical distribution of Black guillemot.    Breeding  Year-round  Nonbreeding
BirdLife International. 2016. Cepphus grylle. The IUCN Red List of Threatened Species 2016: e.T22694861A86848264. https://dx.doi.org/10.2305/IUCN.UK.2016-3.RLTS.T22694861A86848264.en. Downloaded on 06 August 2018.
Cephas