Controlling invasive species - from grey squirrels to American mink - raises complex welfare questions about the ethics and methods of killing animals to protect native ecosystems.
Invasive species management presents a genuine ethical dilemma: native species and ecosystems suffer if invasive populations are not controlled, but the individual invasive animals being killed have the same capacity for suffering as their native counterparts. The welfare question is not whether to manage invasive species but how to do so humanely. Cage trapping followed by shooting provides better welfare outcomes than fumigation or drowning. Fertility control eliminates the welfare cost of lethal methods where effective. The argument for lethal control is strongest where native species welfare is directly threatened - grey squirrel control in red squirrel strongholds, for example. But humaneness should be a non-negotiable standard in any approved management programme.