- Lifespan
- 8–10 years in the wild
- Size & Weight
- 60–90 cm, wingspan 90–125 cm; males 3.5–4.5 kg, females 1.5–2 kg
- Habitat
- Native coniferous and mixed forests with dense understorey, particularly old Caledonian pine forests with bilberry and heather ground cover.
- UK Distribution
- Resident only in the Scottish Highlands, with the largest population in the Cairngorms and other remnant populations in scattered locations; extirpated from the rest of Britain.
- Diet
- Herbivorous; feeds on bilberry, heather, pine shoots, needles, and buds; chicks initially take invertebrates before becoming herbivorous.
- Predators
- Golden eagles, white-tailed eagles, red foxes, pine martens, and crows; eggs and chicks vulnerable to adders and corvids.
- Mating Season
- April to May
- Breeding
- Clutch of 6–10 eggs, incubation period 26–28 days, single brood per year; males perform elaborate dawn leks to attract females.
- Behaviour
- Highly territorial males engage in dramatic competitive displays at traditional lek sites, with elaborate posturing, wing-drumming, and aggressive confrontations. Females are cryptic and solitary, remaining hidden in forest vegetation. Birds are generally sedentary and rarely move far from their territories.