An exclusively marine, medium-sized seabird, occupying rocky coastal regions on steep mainland cliffs and offshore islands (Lavers et al. 2020). Its range extends across the temperate, boreal and low-arctic waters of the N Atlantic. Patchily distributed in Europe, from NW France and the British Isles to Iceland (holding the bulk of population), N Norway, Bear Is and NW Russia (Keller et al. 2020).