Invasive predators like cats, rats and stoats devastate island bird populations, creating welfare trade-offs between controlling invasive species and the suffering of the animals removed.
Invasive predator control creates a difficult welfare calculus. Invasive rats and cats cause immense ongoing welfare harm to native birds through predation - being eaten alive is a significant welfare harm for prey species. Control programs using poison and traps cause welfare harms to the animals targeted. The welfare question is whether the benefit to the larger population of prey species justifies the suffering of individual invasive animals. Most animal welfare ethicists conclude that preventing extinction and the ongoing suffering of many native individuals justifies lethal control of invasives, provided the most humane methods available are used. The development of more humane control tools - including fertility control and gene drives - remains an important welfare research priority.