Invasive predators including rats, cats, and stoats on seabird nesting islands cause catastrophic breeding failures and welfare harms to millions of birds, yet eradication programs have demonstrated remarkable recovery potential.
Invasive predator impacts on seabird colonies represent a welfare catastrophe in slow motion — or sometimes rapid motion. Rats hunting seabird chicks and eggs at night cause deaths that involve predation behavior: pursuit, injury, and ultimately killing of prey that cannot escape. Adult birds lose repeated breeding attempts over years as chicks fail to fledge. The cumulative experience of repeated breeding failure in long-lived seabirds with strong site fidelity is difficult to quantify but represents a sustained reproductive frustration. Eradication programs that remove invasive predators restore breeding success to near-natural rates, demonstrating that the welfare harm is fully reversible given the resources to fund eradication.