Black Guillemot, Cepphus grylle, is a species of colonial seabird found in unvegetated or sparsely vegetated land, coastal and shelf ecosystems. It is a widespread breeder in coastal areas of northern Europe. The species breeds along cliffs and rocky shores. The species is exclusively marine and is a pursuit diver that propels itself through the water using its wings (European Red List 2015).

Cepphus grylle has a breeding population size of 73200-86900 individuals and a breeding range size of 119000 square kilometres in the EU27. The breeding population trend in the EU27 is Decreasing in the short term and Decreasing in the long term.

The EU population status of Cepphus grylle was assessed as Threatened, as the species meets one or more of the IUCN Red List criteria for threatened at the EU27 scale.