"You'd have to pay someone to go out there every day or week to eliminate the rats," said Wallace. "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."
Chile has banned the hunting of penguins through 2024, and since 1978, Islote Pajaro Nino has been one of several sanctuaries established by the government to protect them. Peru also has created sanctuaries and tried to keep predatory animals from critical nesting grounds. But neither country has barred small-scale fishing in the waters surrounding the nesting grounds, and thousands of penguins continue to die in nets each year — as many as 50 at a time in a single net, Arce said.
There's also no Chilean government budget dedicated to protecting penguins from the rats. It was only last week, Simeone said, that he was contacted by officials of the national fisheries service and environment ministry to discuss the situation. Neither agency responded to requests for comment.
Islote Pajaro Nino features steep hills and cliffs of sedimentary rock, surrounded by a narrow beach — ideal nesting grounds for seabirds — and every summer, tens of thousands of seagulls, penguins and pelicans fight over every inch (centimeter) of its 12 acres (5 hectares).
Arce led The Associated Press on a tour of the island, where the detritus of these battles — a slippery mess of excrement, decomposing carcasses, mud and rat feces — was overwhelming. The odor was nearly intolerable to humans, but it could be a paradise for adventurous rodents with a taste for eggs.
The penguins also suffer from competition with pelicans that nest on the ground, collapsing the shallow caves that penguins would otherwise return to each year. Arce pointed to spots where dozens of pelicans had marked their territory in former penguin nests — and to another area where, with help from the Milwaukee Zoo and its foundation, Arce and her team have built dozens of more durable artificial nests for the penguins.
Back at the first nest, six hours have passed with no sign of the young penguin's parents. A little over a mile (2 kilometers) away, a Humboldt swims toward the island. But then it drops under water, and doesn't surface again.
If at least one of its parents fails to appear after another night, the little penguin will succumb to hunger. Or perhaps the rats.
Associated Press Writer Michael Warren contributed from Buenos Aires, Argentina.
Eva Vergara is on Twitter: http//twitter.com/evergaraap
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