- Lifespan
- 10–20 years in the wild
- Size & Weight
- 42–49 cm, wingspan 72–82 cm; 800–1000 g
- Habitat
- Deep freshwater lakes, reservoirs, and flooded gravel pits with good diving depth and abundant aquatic vegetation.
- UK Distribution
- Winter visitor and passage migrant, mainly October to April; small breeding population concentrated in southern England. Numbers have declined significantly since the 1990s.
- Diet
- Aquatic plants, seeds, and invertebrates obtained by diving, with a preference for pondweeds and other submerged vegetation.
- Predators
- Foxes, pike, and birds of prey such as white-tailed eagles and peregrines; gulls may predate eggs and chicks.
- Mating Season
- March to June
- Breeding
- Clutch of 6–10 eggs; incubation period 24–28 days; typically one brood per season. Nests in dense reeds or overhanging vegetation near water.
- Behaviour
- Highly gregarious, forming large flocks in winter, particularly on open water. Males perform elaborate courtship displays with head-flicking and calling. Nocturnal feeders that dive to depths of up to 4 metres to forage.