Ecuador is preparing to massacre more than 180 million rats as it seeks to eradicate them from the Galapagos Islands.
A helicopter will drop nearly 22 tons of specially designed poisonous bait on Pinzon Island, an uninhabited island in the archipelago 600 miles off the coast of Ecuador and the nearby Plaza Sur islet.
It is the second stage in an offensive that aims to kill all non-native rodents across the 19 islands that helped inspire Charles Darwin's theory of evolution by 2020.
Norway and black rats were introduced by whalers and buccaneers when they reached the islands in the 17th century and now feed on the eggs and young of many of the island's native species, including giant tortoises, lava lizards, snakes, hawks and iguanas.
The rats have also depleted the plants on which many natives species feed.
"It's one of the worst problems the Galapagos have. (Rats) reproduce every three months and eat everything," Juan Carlos Gonzalez, a specialist with the Nature Conservancy, said.
"This is a very expensive but totally necessary war."
On Pinzon, which is just seven square miles in area, there are 10 rats for every square metre of land.
The poisoned bait is contained in light blue cubes that attract rats but are repulsive to other inhabitants of the islands.
Thirty-four hawks from Pinzon have been captured in order to protect them from eating the poisoned rodents, while 40 iguanas on Plaza Sur were also held for their own protection.
Asked whether a large number of decomposing rats would create an environmental problem, Danny Rueda, director of conservation for the Galapagos National Park Service , said the poison was specially engineered with a strong anti-coagulant that will make the rats dry up and disintegrate in less than eight days.
The Galapagos were declared protected as a Unesco Natural Heritage site in 1978. In 2007, Unesco declared them at risk due to harm from invasive species, tourism and immigration.