Invasive species cause enormous harm to native wildlife populations. Control programs raise welfare questions that require careful navigation between conservation goals and individual animal welfare.
Invasive species control creates a genuine welfare tension: killing individual invasive animals (rats, stoats, possums) to prevent the suffering and extinction of native wildlife species. The individual animals being killed are not morally culpable for their status as invasives - they are simply living in the environment they occupy. However, the aggregate welfare of native species populations - the billions of bird deaths caused by invasive predators - provides a strong welfare justification for control programs. The welfare case for invasive species control is strongest when killing methods minimize suffering: kill traps that cause near-instant death are preferable to extended dying from poisons, and 1080 poison's welfare impacts are actively debated. Wherever invasive control is necessary, the method should minimize individual animal suffering.