July 12, 2012
Rat Infestation Could Lead To Humboldt Penguin Extinction
redOrbit Staff & Wire Reports - Your Universe Online
While it may sound like the plot for a low-budget fright-fest of a motion picture, the ongoing battle between giant rats and South American penguins on a Chilean island could turn into a real-life horror story for the birds and the environmental activists fighting to keep them from extinction.
According to Eva Vergara of the Associated Press (AP), invading rodents with bodies upwards of eight inches in length have been eating Humboldt Penguin eggs and chicks, leading to concern that the rats could threaten the Spheniscus humboldti population unless they are dealt with.
The medium-sized Humboldt penguins, which are also known as the Peruvian Penguin, have been members of the International Union for the Conservation of Nature's (IUCN) vulnerable list since 1988, Vergara said. A few decades ago, there were hundreds of thousands of the birds in coastal Chile and Peru, but that number has dropped to less than 45,000 in recent years, Alejandro Simeone, director of the Ecology and Biodiversity Department at Andres Bello University, told the AP.
"The Zoological Society of Milwaukee and the county zoo it sponsors, which includes a small Humboldt penguin exhibit, has spent more than $200,000 researching the birds' plight over the years, paying for annual population surveys and providing small stipends to Chilean researchers to make regular visits to the breeding grounds," Vergara said. "That money also supported research published in the March Journal of Ornithology that suggested rats could be devouring penguin eggs at a devastating rate."
As part of that research, Simeone and a team of bird veterinarians placed boiled chicken eggs in empty penguin nests at Islote Pajaro Nino and a second Chilean Island. They discovered that half of them had been eaten by Norway rats at the first location, while 70% were devoured by black rats at the second. Those rats, Simeone said, were attracted to the islands by the elegant flower gardens of the wealthy residents that live there.
According to the AP, "In other parts of the world, such rats have been eradicated using toxic bait that is harmless to birds, but applying such methods here would be complex and costly, Simeone said“¦ Roberta Wallace, the lead veterinarian at the Milwaukee Zoo who has done research on the Humboldt penguins on the island, said it would take poison, and many repeated visits to offshore islands, to break the rats' reproductive cycle. Concerted conservation efforts would be necessary to keep them away."
"You'd have to pay someone to go out there every day or week to eliminate the rats," Wallace told Vergara. "It's not like putting out poison once and everything dies. You'd have to keep at it, because they breed like crazy, and you'd have to make sure you don't do damage to other species. It's logistically a huge challenge."