- Lifespan
- 20–30 years in the wild, with some individuals recorded living over 40 years
- Size & Weight
- 85–100 cm long, wingspan 165–180 cm; 2.6–3.5 kg
- Habitat
- Coastal waters and rocky islands with sheer cliffs, breeding on isolated colonies with minimal disturbance.
- UK Distribution
- Summer breeder at major colonies including Bempton Cliffs (Yorkshire), Bass Rock (Scotland), Helgoland (off Wales), and Grassholm (Wales); winters in Atlantic waters off western coasts and occasionally seen in British waters year-round.
- Diet
- Primarily fish, especially herring, mackerel, sand eels, and other marine fish species, caught by plunge-diving.
- Prey
- Herring, mackerel, sand eels, capelin, and other small to medium fish
- Predators
- Great Black-backed Gull (predates chicks and eggs); historically persecuted by humans; virtually no natural predators of adults
- Mating Season
- March to October, with peak breeding April to August
- Breeding
- Single egg per clutch, incubation period 42–46 days, fledging at 11–13 weeks; one brood per year
- Behaviour
- Highly colonial, breeding in thousands at traditional sites with strong nest fidelity. Spectacular plunge-divers, entering water at speeds up to 100 km/h with specialised skull adaptations. Form long-term pair bonds and return to same nest site annually.