She kills to be kind: the mastermind ecologist eliminating invasive predators

Honed in New Zealand and exported globally, Elizabeth Bell's techniques for creating predator-free zones are allowing native species to thrive again on islands from the Caribbean to the UK

In the middle of the night, nine-year-old Elizabeth Bell sprints through the narrow bush tracks of Maud Island, racing toward the nearest ridgeline. The darkness beyond her is almost total. There is no ambient glow from distant city street lights: the island is a 1.2 sq mile (3.2 sq km) uninhabited speck covered with forest, off the northern tip of New Zealand's South Island.

Somewhere out there in the 1am darkness, on tracks skirting the dense, latticed native forest, her siblings are running too, sprinting for the other headlands. They listen for the sound of distant booming, resonant and low, like the throb of a timpani drum or the buzz of a phone on a hard table.