Eradication campaign for rats devastating the islands

Nearly 22 tons of specially-designed poison bait is being dropped on one of the Galapagos islands, in order to help clear non-native rodents from the group of islands.

Ecuadorean authorities say the invasive Norway and black rats need to go, because they are threatening the islands' native species by depleting plants that they feed on and eating their eggs.

The hundreds of millions of rats will be poisoned as part of a campaign to eradicate them from the islands by 2020, in order to preserve the affected species, which include giant tortoises, lava lizards, snakes and iguanas.

The rats have also critically endangered bird species living on the cluster of 19 islands that were declared protected as a UNESCO Natural Heritage Site in 1978.

"It's one of the worst problems the Galapagos have. [Rats] reproduce every three months and eat everything," said Juan Carlos Gonzalez, a specialist with the Nature Conservancy involved in the current phase of the eradication operation, which is costing the national park and non-profit conservation groups $1.8million (£1.1million).

"This is a very expensive but totally necessary war."

The rats were introduced to the islands by whalers and buccaneers in the 17th century.