An expert leading an experiment to lure the cliff swallows back to the Mission San Juan Capistrano for its annual celebration of the birds in March said Wednesday he is going to try a new tactic since amplified courtship calls have had little success.
Charles Brown, a professor of biological sciences at the University of Tulsa, told City News Service this year is the final time that the Swallows Vocalization Project, which involves speakers loudly playing the bird’s courtship calls and songs to attract them to the historic mission, will be deployed.
“We’re going to try the playback one more year, but it’s looking like it might not be enough to lure them,” Brown said. “It’s beginning to look like we may have to take more drastic action, but we’re going to give it one more shot and see if we can get some interest.”
The project has enjoyed a bit of success in reviving the annual visit of the swallows, which went from healthy populations in the 1980s to virtually no birds now.
“We know that birds have investigated and there’s been a couple of sightings of birds checking out the stone church, likely in response to the vocalizations, and there was a pair that nested on the mission two years ago,” Brown said. “But we haven’t been able to attract very many.”
The next trick will be to construct a wall with plaster nests, he said.
“The hope is if they see the nests, they’re more likely to stay,” Brown said. “We’re in the planning stages for that, and about a year away from that probably.”
Swallows are typically on the prowl for old nests to reuse since it’s much easier than building one from scratch, Brown said. Sometimes the plaster nests, if they’re the right size, will be deemed good enough, he said.
“We think the artificial nests are the last, best shot,” Brown said.
Putting together a wall of the nests will be tricky since it has to match the aesthetics of a historic building and the labor costs could be challenging, Brown said.
“We can get mission volunteers doing that, but it’s more of a time issue in crafting these nests. But we do have models already,” he said.
The main reason the swallows avoid San Juan Capistrano is the popularity of trees in the area.
“These birds avoid wooded areas,” Brown said, explaining that trees cut down on surges of warm air that lead to a swarm of insects the swallows feast upon.
“They feed on swarms of insects and these swarms of insects tend to occur in open terrain,” Brown said.
The 57th annual Swallows Day Parade is scheduled for March 21.
— City News Service