Environment & Science

San Juan Capistrano’s swallows may be coming back

The mission at San Juan Capistrano is hosting its first pair of nesting cliff swallows in years. Large nesting colonies of the birds made the mission famous in the early 1900s but they've been largely absent in recent decades.
The mission at San Juan Capistrano is hosting its first pair of nesting cliff swallows in years. Large nesting colonies of the birds made the mission famous in the early 1900s but they've been largely absent in recent decades.
Jill Replogle

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San Juan Capistrano is famous for the cliff swallows that come back to the town’s 18th century Spanish mission every spring to nest — or so the legend goes. In reality, it’s been nearly 30 years since the mission had a colony of the migratory birds. But there are signs they may be coming back.

In early May, a pair built one of the species’ signature gourd-like mud nests in a corridor of the mission. Megan Dukett, the mission’s education program manager, said she’s seen up to 15 swallows darting around above the mission grounds in recent weeks.

“We’re hoping that more birds are going to look to build nests here and create a little colony of cliff swallows,” she said.

Cliff swallows winter in South America and migrate north to California and elsewhere across the U.S. in the spring. The Mission at San Juan Capistrano was known to have a large colony of cliff swallows at least since the early 1900s and up until the late 1980s. 

Work done to stabilize and retrofit the ruins of an old church at the mission cut off one of the most popular nesting areas, Dukett said, and the mission’s cliff swallow population began to decline.

Biologist Charles Brown lined a wall at the mission in 2015 with imitation, plaster cliff swallow nests in hopes of luring the birds back. The nests remain unused.
Biologist Charles Brown lined a wall at the mission in 2015 with imitation, plaster cliff swallow nests in hopes of luring the birds back. The nests remain unused.
Jill Replogle

In 2012, mission staff hired Charles Brown, a biologist from the University of Tulsa, to help bring the swallows back. He set up a looping broadcast of recordings he made elsewhere of cliff swallow mating calls and nesting colonies. 

When that didn’t pan out, he built a fake wall with an arch and lined the arch with imitation, plaster nests in hopes the birds would welcome the prefab homes as an alternative to the laborious process of building a nest from bits of mud. 

Brown said it’s unclear what brought the current nesters, but he suspects it wasn’t his work. Rather, he thinks it was the presence of another species, the rough-winged swallow, that attracted them. A pair of rough-winged swallows took up residence at the mission earlier in the spring. 

"Live decoys are a lot better than plaster nests or tape recordings,” he said. “Cliff swallows are highly social animals.” 

Brown said sustaining a large nesting population, however, could be difficult. Cliff swallows appear to be undergoing a long-term decline in Southern California, he said, likely because of drastic changes to the landscape including the replacement of open grasslands with trees and other landscaping.

Cliff swallows feed on swarms of insects that congregate over open land and near water. 

But Dukett is hopeful for a renewed colony at the mission. 

“They’re a symbol of hope, and that is what we really have here as a community, as a town, a hope for their return,” she said.