Rat eradication from seabird colonies has produced dramatic increases in puffin and other seabird breeding success, representing one of the most effective conservation welfare interventions available.
Rat eradication from seabird islands involves a welfare trade-off between rats killed in the eradication operation and the prevention of ongoing chick predation. The scale arithmetic strongly favours eradication: a single rat can consume many chicks per breeding season, across many years, and across multiple species. Puffins and other seabirds on rat-free islands show dramatically improved breeding success, meaning significantly more young birds experiencing normal life rather than being killed in the nest. Post-eradication recovery is rapid and dramatic, validating the welfare calculus for targeted island eradications.