Scientists are planning an operation to save seabirds on the Pitcairn Islands. Henderson petrels are one of four rare birds that are found only on the island. They are under threat because their chicks are being eaten alive by rats with which the island has become infested. Nearly 50 million pellets of rat poison will be dropped on the islands in an effort to save the birds. Other species that are threatened include the Henderson reed-warbler, the Henderson crake, the Henderson fruit-dove and the Henderson lorikeet. The operation will cost around £1.7 million and the whole island will need to be covered with around 98 tonnes of cereal pellets. For it to be successful is would be essential that no single pregnant rat remains alive.