Rare seabirds nesting on Chilean island after invasive species removed

For the first time in more than 40 years, a Peruvian diving petrel chick has hatched on Chañaral Island in Chile, marking a milestone on an island once devastated by invasive species. Members of the non-profit Island Conservation team, working in partnership with the National Forestry Society of Chile (CONAF), The Nature Conservancy and Universidad Católica del Norte, discovered a fluffy chick in a naturally dug burrow – a breakthrough that offers hope for a species considered “endangered”. by the International Union for Conservation of Nature (IUCN) just two years ago.

An island healing from destructive invasive species

Peruvian diving petrels (known locally as “yuncos”) are small, ground-nesting seabirds endemic to the Humboldt Current system that flows along the west coast of South America. Chañaral Island, located just a few kilometers off the coast of Chile, was once home to what may have been the largest population of this species in the world before the introduction of invasive rabbits and foxes many years ago. Coral Wolf, conservation science program manager at Island Conservation, explains the negative impact this has had over the years:

“Rabbits and foxes have decimated the sensitive desert landscape of the island. Foxes fed on yuncos, while rabbits ejected them from their nests and stripped grasses and shrubs. As a result, the number of diving petrels has decreased significantly. Eventually, no diving petrels lived in Chañaral, and in the region they could only be found on a handful of islands. They were in danger of disappearing on a global scale.

However, in 2013, to restore and rewild the Humboldt Penguin National Reserve, Island Conservation and CONAF launched a project to eradicate invasive rabbits from Chañaral and neighboring Choros Island.

“Since the invasive rabbits were successfully eradicated in 2017 and without foxes on the island for many decades, we have focused on restoring Peru’s diving petrel population and building their resilience as well as that many other species unique to this region. “, says Wolf.

Use social attraction to boost population

A Peruvian petrel chick on the island of Choros. Photo: Center for Advanced Studies in Arid Zones (CEAZA)

In September 2019, Island Conservation, CONAF and Universidad Católica del Norte (with technical support from Project Puffin) launched a social attraction project in Chañaral. Social attraction methods exploit the natural behavior of seabirds by mimicking the sights and sounds of a real breeding colony, for example by playing bird calls over an audio system. Cristian Rivera, ranger at Chañaral Island Park in the Humboldt Penguin National Reserve, details Chañaral’s unique approach:

“We used artificial PVC nests and two sets of solar-powered speakers that broadcast petrel calls to attract nearby adults to nest on the island,” he recalls. “It was one of the first projects of this type on a Chilean island. Just days after the two sound systems were installed, petrels began arriving on the island to explore the surrounding area.

A long-term monitoring project was then launched, with funding provided by the American Bird Conservancy (for the first year) and the David and Lucile Packard Foundation. Soon enough, motion-sensing cameras documented the petrels’ frequent presence at the two established social attraction sites. In addition, many footprints were recorded while exploring artificial nests, and a year and a half after the implementation of the project, the construction of the first natural burrows was detected.

“Just three years into the project, our team had already found three naturally dug burrows, and an incredible surprise awaited them,” Rivera says. “Using a burrowscope, which allows us to see deep inside a nesting chamber, we were able to observe our first documented Peruvian diving petrel chick on the island for at least 40 years! »

A model for global seabird conservation and a bright future for Chanaral’s yuncos

Seabirds are the most threatened group of birds globally. However, Nick Holmes, associate director for oceans at The Nature Conservancy of California, points to the value of restoration methods like social attraction in reversing this trend:

“Seabird restoration approaches, such as social attraction, have high success rates and are powerful ways to protect threatened populations and restore the key role of seabirds in island ecosystems,” he says. he. “The restoration of Chañaral as a breeding colony of yunco once again strengthens the resilience of the population throughout the Humboldt Current.”

Island restoration specialist María José Vilches says this success will have a ripple effect on conservation in the region:

“Lessons learned from social attraction sites in Chañaral have sparked interest in deploying social attraction tools at suitable additional sites nearby,” she says. “For example, Island Conservation is planning to add social attraction sites for Peruvian diving petrels on the island of Pajaros Uno, where we have managed to eliminate invasive rats introduced by humans by mistake and which, in a short time time, have made it impossible for yunco colonies to migrate to survive.This work gives hope to these incredible creatures, which were on the verge of permanently losing their natural habitat.

This project not only benefits local Yunco habitats; the islands are part of an interconnected coastal system that is vital for multiple endemic plants and animals. “The Humboldt Current upwelling system contains globally significant biodiversity,” says Guillermo Luna of the Universidad Católica del Norte. “In addition, some communities depend on sustainable ecosystems for fishing and tourism. This is why it is essential to integrate all these coastal islands into an overall system of conservation and management.

For Jorge Carabantes, head of protected natural areas at CONAF Atacama, the results obtained so far are a good surprise and give hope that the island can return to its natural state. “Not only did we focus on destructive rabbits, but we also worked to control several other invasive species, such as the aggressive Mesembryanthemum (ice plant). With continuous planning, implementation and patience, we offer Mother Nature a helping hand in achieving ecological balance.

Thanks to Island Conservation for providing us with this news.