Rat kill in Galapagos Islands targets 180 million

A helicopter is to begin dropping nearly 22 tons of specially designed poison bait on an island Thursday, launching the second phase of a campaign to clear out by 2020 non-native rodents from the archipelago that helped inspire Charles Darwin's theory of evolution.

The invasive Norway and black rats, introduced by whalers and buccaneers beginning in the 17th century, feed on the eggs and hatchlings of the islands' native species, which include giant tortoises, lava lizards, snakes, hawks and iguanas. Rats also have depleted plants on which native species feed.

The rats have critically endangered bird species on the 19-island cluster 600 miles (1,000 kilometers) from Ecuador's coast.

"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 Phase II eradication operation on Pinzon island and the islet of Plaza Sur.

Phase I of the anti-rat campaign began in January 2011 on Rabida island and about a dozen islets, which like Pinzon and Plaza Sur are also uninhabited by humans.

The goal is to kill off all nonnative rodents, beginning with the Galapagos' smaller islands, without endangering other wildlife. The islands where humans reside, Isabela and Santa Cruz, will come last.

Previous efforts to eradicate invasive species have removed goats, cats, burros and pigs from various islands.

Pinzon is about seven square miles (1,812 hectares) in area, while Plaza Sur encompasses just 24 acres (9.6 hectares).

"This is a very expensive but totally necessary war," said Gonzalez.