The sad case of the Norfolk Island morepork shows we need a way to control or eradicate invasive rodents without killing native species. When pest rats and mice decimate populations of native species, pest control is a no-brainer. But what if baiting rats protects threatened songbirds, while poisoning critically endangered owls?

This is a question conservation managers are grappling with on tiny Norfolk Island, some 1,300 kilometres off the east coast of Australia. They’re not the only ones troubled by such conflicting priorities.

Rodents are implicated in the decline of at least 400 threatened species and 30% of bird, mammal and reptile extinctions worldwide. Unfortunately, the most effective rat baits can also kill birds of prey.

Our new research shows the critically endangered Norfolk Island morepork is eating even more rats and mice than previously thought. These birds of prey are being poisoned in the process. We clearly need a way to control or eradicate rodents without killing our native species.