Rediscovery of the Scottish polecat, Mustela putorius: Survival or reintroduction?

The recent rediscovery of the polecat (Mustela putorius) in Scotland has raised the question of whether the species has been present at low abundance all along or was covertly reintroduced. We assess the exceptionality of the recent sighting. The analysis suggests that the polecat was reintroduced.