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Elusive seabird breeding grounds discovered in Chilean desert

  • A Chilean expedition into the Atacama Desert has located the first known breeding grounds of the ringed storm-petrel, a seabird of unknown population size that is endemic to the western coast of South America.
  • The nests, located in natural cavities in the desert’s rocks and salt pans, were found 70 kilometers (44 miles) from the Pacific coast, where the birds feed and spend most of their time.
  • Chilean scientists see the discovery as critical to estimating the stability and size of the ringed storm-petrel population and determining the threat posed by mining and proposed wind farms in the region.

In a search to locate the nesting grounds of the ringed storm-petrel (Oceanodroma hornbyi) a team of Chilean biologists didn’t rely on high-tech tracking devices or aerial mapping tools. Instead they followed their noses.

A small team of scientists and volunteers from the Chilean Network of Ornithologists (Red de Observadores de Aves y Vida Silvestre de Chile — ROC) had ventured into the Atacama Desert of northern Chile, one of the driest places on earth, looking for evidence of this elusive seabird. They were in a region 70 kilometers (44 miles) from the Pacific coast when they caught a whiff of the birds’ distinctive musty odor.

“It’s not unlike old socks with a bit of fish thrown in,” Josh Adams, a biologist specializing in storm-petrels at the United States Geological Survey who was not a part of the ROC team, told Mongabay.

The Chilean team searches the Atacama Desert for signs of ringed storm-petrel nests. Photo by Filipe de Groote.

Spreading out over the rocky, salt encrusted landscape, the scientists and volunteers poked around in holes and crevices. They discovered feathers from an unidentified species of storm-petrel, confirming that the birds were using the small, naturally-formed cavities as nests, Heraldo Norambuena Ramirez, one of the ROC biologists, told Mongabay by email.

And then, in one of the nests, they found the small gray and black bird they’d been searching for. By the end of the day, they had identified 25 active nests, but no other birds or eggs. ROC announced the discovery in a press release late last month.

Birders often spy ringed storm-petrels flitting across open waters off the Chilean coast, but the location of their breeding grounds has confounded ornithologists for decades. Mummified remains of the birds, also known as Hornby’s storm-petrels, had been found in the Atacama Desert, where ROC expeditions recently revealed nesting colonies of a related species, Markham’s storm-petrel (Oceanodroma markhami).

This naturally formed hole in the desert’s salt crust has been used by a ringed storm-petrel as a nest. Photo by Felipe de Groote.

The discovery is critical to understanding the ringed storm-petrel’s biology, estimating its population size, and determining whether mining activity and proposed wind farms in the Atacama Desert pose a danger to its continued existence.

“That’s the first step of conservation,” said Adams, “knowing where these unique animals are living, and how to preserve their habitat.”

The Humboldt Current, which flows along the west coast of South America, sustains numerous species of storm-petrel. The birds only venture onto land to breed and nest, and that is also when they are most vulnerable. To avoid rodents, snakes, and other predators, they often choose isolated, difficult-to-access spots like cliff faces, rocky islands, and barren deserts like the Atacama. The almost complete lack of precipitation renders the Atacama nearly uninhabitable, making it safe for Markham’s storm-petrels, and apparently ringed storm-petrels, to leave their chicks behind while they commute to the sea to feed.

From the five known Markham’s storm-petrel breeding colonies, Ramirez and his colleagues have obtained a clearer picture of the birds’ breeding behaviors and their numbers. They believe that they can replicate that approach with the ringed storm-petrel. They plan to search for additional colonies in the likeliest 400-square-kilometer (150-square-mile) region of desert. If they manage to find some, they will be able come up with a better estimate of the ringed storm-petrel population. Current estimates range widely, from 700 to 60,000 adults.

Ringed storm-petrel in flight. Photo by Rodrigo Moraga.

That information is important because the Atacama Desert is quickly becoming less desolate, as a result of both traditional and emerging industries. Lights from mining facilities attract and disorient storm-petrels, especially the juveniles on their first flight to the sea.

And with the Chilean government’s ambitious goal of obtaining 70 percent of its energy from renewable sources by 2050, the Atacama Desert is seen as a good location to build solar and wind farms. A 56-turbine farm was recently built on the coast of Huasco province, significantly to the south of the ringed storm-petrels’ nests.

Wind turbine blades rotate too quickly for even a fast bird like the storm-petrel to avoid, said Michael Hutchins, a behavioral ecologist who directs the Bird-Smart Wind Energy campaign for the American Bird Conservancy (ABC), which supports ROC’s storm-petrel work. The problem is compounded by the storm-petrels’ preference for flying at night, when the turbines are most active.

“A big part is proper placement of the turbines, away from high concentrations of birds,” said Hutchins, speaking of ABC’s campaign. If wind farms are built in the flight paths that storm-petrels take to get to their nests, the effects could be devastating.

Currently none of the storm-petrel colonies are protected in Chile. “In general [most Chileans’] idea is that in the desert is nothing,” said Ramirez.

He hopes that news of the ringed storm-petrel nest discovery will raise awareness of the bird’s plight and prompt the government and businesses to mitigate the any harm caused by mines and wind turbines.

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A ringed storm-petrel caught in a nest, confirming that the team had found the location of a breeding colony. Photo by Felipe de Groote.