Pine martens are being reintroduced to Wales following local extinction, with complex implications for the welfare of the martens themselves and for squirrel, songbird, and other prey populations.
Reintroduction of pine martens involves direct welfare considerations for translocated individuals — stress of capture, transport, and release into unfamiliar territory — and for established populations exposed to vehicle collisions and illegal persecution. Prey species welfare is also relevant: martens are efficient predators that typically kill prey quickly, and their presence creates fear responses in prey populations that can influence habitat use and behaviour. The net ecological effect of marten recovery — including reduction of grey squirrels and potential benefits for ground-nesting birds — involves welfare trade-offs at the community level. These are complex but important considerations for rewilding ethics.