- Lifespan
- 25–30 years in the wild, with some individuals recorded living into their thirties
- Size & Weight
- 38–41 cm long, wingspan 64–71 cm; 900–1,050 g
- Habitat
- Rocky coastal cliffs and offshore islands where they nest in dense colonies, spending winters at sea.
- UK Distribution
- Found around the coasts of northern Scotland, northern England, Wales, and southwest England; resident year-round with population increases during breeding season.
- Diet
- Primarily small fish including sand eels, sprats, and capelin, caught by diving to depths of 30–40 metres.
- Prey
- Sand eels, sprats, capelin, herring, and other small fish species
- Predators
- Great black-backed gulls, herring gulls, white-tailed eagles, and occasionally foxes and rats on breeding colonies
- Mating Season
- April to August
- Breeding
- Single egg laid directly on bare rock ledges with no nest material; incubation period of 28–29 days; fledging at 18–25 days when chick is still flightless
- Behaviour
- Highly colonial breeders forming dense nesting aggregations on cliff faces; excellent swimmers and divers relying entirely on wing-propulsion underwater. Males and females form long-term pair bonds and return to the same nest site annually.