South Georgia declared rat-free after centuries of rodent devastation

World's biggest project to kill off invasive species to protect native wildlife is hailed a success

• In pictures - South Georgia's huge rodent eradication project

The world's biggest project to eradicate a dangerous invasive species has been declared a success, as the remote island of South Georgia is now clear of the rats and mice that had devastated its wildlife for nearly 250 years.

Rats and mice were inadvertently introduced to the island, off the southern tip of South America and close to Antarctica, by ships that stopped there, usually on whaling expeditions. The effect on native bird populations was dramatic. Unused to predators, they laid their eggs on the ground or in burrows, easily accessible to the rodents.