The cliff swallows of Mission San Juan Capistrano in California have been the source of an annual celebration for around two centuries. Like clockwork, the birds have arrived in the thousands every year on March 19, Saint Joseph's Day, to rebuild their nests and raise their chicks. Over the years, their punctuality and the spectacle of so many birds has turned the annual migration and arrival into a celebration, and there is even a parade held in their honor. However, in recent years, those high expectations have turned to dashed hopes as the swallows have passed by the mission for other nesting sites.

Mission San Juan Capistrano was once the tallest building in the area, meaning it had a natural appeal to these cliff-dwelling birds. Located near two rivers, the spot provided plenty of insects for food and, of course, all the lodging they needed. It was the perfect place to return to, and the swallows did so faithfully each spring. But southern California has seen a good deal of urbanization over recent decades, creating a larger variety of potential nesting sites. This, along with restoration efforts at the mission that destroyed old nests, which the swallows use to start their new nests, has meant that the mission is no longer the destination for these birds. The swallows have looked elsewhere for more ideal nesting locations, and have moved to overpasses, bridges and even a country club in Chino Hills.

cliff swallows and nests Swallows use old nests as a starting point for their new nests. (Photo: Don McCullough/Flickr)

But the folks at the mission haven’t given up yet. They hope to attract the birds back to their former nesting grounds by using recordings of mating calls. Dr. Charles Brown, a cliff swallows expert, established the vocalization project. Speakers placed behind a statue play the courtship calls of the species. After initially trying it in 2012, a few swallows were sighted feeding overhead and flying in to investigate. So far the birds have not come back to reestablish their old nesting site, but that doesn't mean the end of efforts to bring them back. The vocalization program this year began in February. Perhaps there’s a chance they will return this year, as the vocalizations play on.

"I think if we keep trying long enough, eventually, some individuals will come by, they'll see the mission and they will realize it's a good place to nest, as they did in the past,” Brown says.

And just in case, the annual festival celebrating the return of the swallows, Fiesta de las Golondrinas, will continue, as it has for so many years.

swallows viewing area The birds have traditionally arrive in March on St. Joseph's Day, and they stay until late October on the Day of San Juan. (Photo: MargaretNapier/Flickr)

Jaymi Heimbuch ( @jaymiheimbuch ) focuses on wildlife conservation and animal news from her home base in San Francisco.

Bringing back the famous swallows of Mission San Juan Capistrano
The birds have returned like clockwork annually for centuries.