The management of invasive grey squirrels to protect native red squirrels raises difficult welfare questions about lethal control, contraception, and the ethics of species management.
Grey squirrel management presents a classic conservation welfare dilemma: how to balance the welfare of individual grey squirrels against the welfare and survival of red squirrel populations. Grey squirrels are intelligent, social animals capable of experiencing pain and stress - lethal control methods including shooting, trapping, and drowning cause direct welfare harm to the animals killed. Yet without population control, red squirrels - which may be more emotionally salient due to their rarity and cultural status - face local extinction and the welfare consequences of squirrelpox infection, which causes a prolonged and painful death. Humane trapping followed by lethal injection is considered preferable to drowning, which was previously common. Immunocontraception offers a potential future solution that would reduce grey squirrel reproduction without lethal methods, but is not yet available at scale. The philosophical question of whether it is ethically acceptable to cause welfare harm to abundant invasive species to protect native species is unresolved and depends partly on how much moral weight is given to species-level versus individual animal welfare.