Pine martens have recovered dramatically in Scotland and are being reintroduced to Wales and England. Their welfare and their role in suppressing grey squirrel populations raises complex ethical questions.
Pine marten welfare in translocation programmes involves capture stress, transport, and release into unfamiliar territory. Radio collar monitoring requires periodic recapture for collar adjustment. Wild pine martens face welfare harms from territorial conflicts, starvation in harsh winters, and road casualties as their range expands. The interesting ecological dimension is that pine marten recovery causes welfare harm to individual grey squirrels through predation — but may support red squirrel population recovery. This creates a situation where supporting one native species necessarily involves accepting welfare harms to another, non-native species. The ethics of restoration ecology regularly encounters these tensions.