Red squirrels in the UK are confined to refugia by competition and squirrelpox virus carried by grey squirrels, creating ongoing welfare and conservation challenges.
Squirrelpox causes swelling, scabbing and lesions over 2-3 weeks before death in red squirrels — a prolonged welfare harm. Grey squirrel control through trapping and shooting raises welfare concerns for grey squirrels, which are sentient animals despite their invasive status in the UK. Immunocontraception for grey squirrels is under research as a potentially more welfare-positive management approach. Managing these competing welfare concerns is central to conservation policy.