Manx shearwaters nest in burrows on offshore islands and are devastated by introduced rats, requiring ongoing rodent control for successful breeding.
Shearwater chicks predated by rats in burrows die from wounds inflicted in the confined space of their nest burrow. Adult birds incubating eggs or brooding chicks are also killed by rats. The colony abandonment that follows rat establishment represents long-term reproductive failure for thousands of highly site-faithful individuals. Rat eradication programs on islands cause acute suffering to the rodents removed but prevent far greater ongoing suffering across entire seabird colonies.