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Chilean island popular with seabirds declared rat-free

Humboldt Penguin. Photo courtesy Island Conservation

On December 2, the Chilean Ministry of Environment and the international nonprofit organization Island Conservation declared Chile’s Pajaro Uno Island free of invasive rodents. The partners removed invasive rats to restore the island’s native seabirds and protect the marine environment.

Invasive rats on the island were devouring Chilean seabird eggs and chicks. Seabirds deposit critical nutrients from the sea to the land through their guano, which then runs off into the nearshore waters to sustain reefs. The loss of these nutrients can cause devastating effects to the terrestrial and marine environment.

Pajaro Uno Island is home to multiple colonies of Chilean seabird species. The 70-hectare island supports important seabird breeding populations: about 3,000 pairs of Peruvian Boobies, the largest population of Kelp Gulls in northern Chile with about 2,000 pairs, and about 600 breeding pairs of vulnerable Humboldt Penguins.

In August 2020, thanks to the support of David and Lucile Packard Foundation, Island Conservation staff traveled to Pajaro Uno Island to implement conservation actions to protect native birds by removing invasive rats.

After two years and several native species monitoring trips later, the team returned to the island to implement a Rapid Eradication Assessment. This assessment collected evidence confirming rats were no longer present. With this fantastic news, efforts can begin to rewild the island by enticing once-present seabird species to return, thus accelerating the recovery of the terrestrial and marine ecosystems to their natural potential.


“This is very good news. Invasive species remain a problem on other islands in the country. Through the removal of invasive species and effective biosecurity to prevent reintroduction, we can support the recovery of ecosystems and protect biodiversity,” said Maisa Rojas, Chile’s Minister of the Environment. “The successful restoration of Pajaro Uno is a step that demonstrates our commitment to ecological restoration and nature protection. The entire world is facing a biodiversity loss crisis, so all recovery actions are crucial.”

“Before the impact of rats on the island, Pajaro Uno was an important nesting site for the Endangered Yunco (or Peruvian Diving-petrel),” said Maria Jose Vilches, Pajaro Uno Project Manager for Island Conservation. “This species was extirpated from the island, but we hope to encourage their return through social attraction like we successfully did on Chanaral Island, Chile.”

Pajaro Uno Island
Pajaro Uno Island. Photo courtesy Island Conservation

Invasive rats on islands are a major cause of species extinctions globally, particularly for seabird species. They were unintentionally introduced to Pajaro Uno Island years ago as a vessel stowaway associated with human use of the island.


The Pajaro Uno project used a new methodology which required less conservation bait. This lowered the risk of non-target exposure and decreased the cost of the project.

“Pajaro Uno Island and surrounding sectors on the continent are priority sites for the conservation of Chilean biodiversity due to the high endemism that the area houses. Ecological restoration projects that ensure the recovery of native species in the future are of great importance to us,” said Daniela Manuschevich, Head of the Natural Resources and Biodiversity Division of the Ministry of the Environment.

Pajaro Uno Island is located in front of Caleta Hornos in the commune of La Higuera and is part of the Coquimbo Coastal System, an ecosystem comprised of seven islands that together with their surrounding waters support not only large colonies of endangered and emblematic seabirds that breed on the islands, but also migratory seabirds and marine mammals.

To learn more about this project or donate to Island Conservation, please click here.


Thanks to Island Conservation for providing this news.

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