The capercaillie is Britain's largest grouse and one of its most endangered birds. Restricted to fragments of ancient Caledonian pine forest in Scotland, its welfare is critically tied to habitat quality.
Capercaillie welfare at the individual level is directly affected by fence collision mortality, predation risk, and disturbance. Fence marking - adding visual deterrents at low heights - has been shown to significantly reduce collision mortality. Predator management around key nesting areas reduces egg and chick predation. Human disturbance from walking in capercaillie habitat during the breeding season causes stressed behavior and nest abandonment. The total UK population is so small that individual birds matter significantly to the species' survival.