Galapagos National Park via AP

Galapagos National Park staff on Monday test equipment that will hold poisonous bait to kill rats.

A helicopter on Thursday began dropping 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 from Ecuador's coast.

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 in area, while Plaza Sur encompasses just 24 acres.

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

The rat infestation has now reached one per square foot on Pinzon, where an estimated 180 million rodents reside.

The director of conservation for the Galapagos National Park Service, Danny Rueda, called the raticide the largest ever in South America.

Galapagos' Lonesome George might not have been last of his kind

The poisoned bait, developed by Bell Laboratories in the United States, is contained in light blue cubes that attract rats but are repulsive to other inhabitants of the islands. The one-centimeter-square cubes disintegrate in a week or so.

Park official Cristian Sevilla said the poison will be dropped on Pinzon and Plaza Sur through the end of November.

A total of 34 hawks from Pinzon were trapped in order to protect them from eating rodents that consume the poison, Sevilla said. They are to be released in early January.

On Plaza Sur, 40 iguanas were also captured temporarily for their own protection.

Asked whether a large number of decomposing rats would create an environmental problem, Rueda 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 without a stench.

It will help that the average temperature of the islands is 75 degrees Fahrenheit, he added.

The current $1.8 million phase of the project is financed by the national park and nonprofit conservation groups including Island Conservation.

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. 

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Lonesome George, the giant tortoise who became the face of the Galapagos Islands conservation effort, was found dead in his corral Sunday morning, according to a statement by the Galapagos National Park Service. He was believed to be more than 100 years old and weighed 200 pounds.

He is the last known Pinta Island giant tortoise, and his death likely marks the complete extinction of his subspecies.

Fausto Llerena, Lonesome George’s longtime caretaker, discovered the tortoise stretched out, leaning toward his watering hole. The cause of death remains undetermined and the tortoise’s body is being held in a cold chamber to avoid decomposition before officials conduct a necropsy, the park said.

For years, Lonesome George’s minders tried to encourage him to procreate, even offering $10,000 for a pure Pinta Island tortoise. The reward went unclaimed, and park conservationists brought in four female tortoises of similar species, but their eggs proved infertile.

Sveva Grigioni, a 26-year-old Swiss zoology graduate student, nobly contributed to the effort by attempting to manually stimulate George, according to “Lonesome George: The Life and Loves of a Conservation Icon,” a book by Henry Nicholls about the famous tortoise.

Grigioni’s work wasn’t completely for naught, as George started showing interest in the females in his corral.

“He started to try copulation but it was like he didn’t really know how,” Grigioni told Nicholls, according to a book review in the Guardian of London.

The giant tortoise is native to several of the Galapagos Islands, a volcanic archipelago west of the Ecuadoran mainland. Lonesome George was the last known individual of the Pinta Island tortoise subspecies (Chelonoidis nigra abingdoni).

A scientist studying snails spotted the tortoise later known as Lonesome on Pinta Island in 1971. The tortoise was brought to the Darwin research station the following year.

He was named Lonesome George (or Solitario Jorge) for George Gobel, the television star who played, according to a 2007 in The New York Times, the role of a “hapless, hen-pecked husband."

Some 20,000 giant tortoises of different subspecies still live on the Galapagos, according to Reuters.

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