While birds and airports generally aren’t a good mix, the combination has been a real winner at San Diego International Airport through a successful endangered species preserve located next to the facility’s single runway.
In what has to be one of the oddest places and certainly the noisiest for a nesting preserve, increasing numbers of California least terns mate, eggs are hatched, and fledglings are nurtured just a few dozen feet from the deafening roar of commercial jets.
The tiny birds, just 6 inches tall and weighing 1.6 ounces, have been making their nests in and around San Diego’s main airport, also known as Lindbergh Field, for thousands of years and they aren’t leaving anytime soon, said Robert Patton, a biologist contracted by the San Diego Zoological Society to monitor the preserve.
“It’s amazing how rapidly they habituate to that site,” Patton said.
The nests are located in five vacant parcels in the southern part of the airport, mainly concentrated in a 5-acre area adjacent to the old Teledyne Ryan company site.
This year, 135 terns hatched from nests at the preserve, making it one of the most productive sites for the birds in the county, Patton said.
However, it’s not even close to the best nesting preserve found at Marine Corps Base Camp Pendleton in the North County where an average of 1,500 nests are created annually, he said.
Not all nests produce a fledgling after a 21-day incubation period because the birds attract lots of predators.
“Just about anything that can, will try to eat them,” Patton said. The list includes hawks, falcons, owls, kestrels, seagulls, rats, cats and even red ants.
As development encroached upon the terns’ nesting areas on beaches throughout California, the terns’ population was decimated. As of 1973, 600 pairs survived, but environmental mitigation efforts, such as the six preserves in San Diego County, have helped restore the statewide population to about 7,000 pairs as of last year, Patton said.
Because of the birds’ recovery, the U.S. Fish and Wildlife Service recommended last year to reclassify their status from endangered to threatened, a move Patton disagrees with.
“They’ve declined in productivity in recent years, and we may have a population crash coming in the next few years,” he said.
The efforts to maintain a nesting preserve at Lindbergh Field dates back to when an environmental impact report was prepared before an extensive airport renovation project in the mid-1990s, said Richard Gilb, manager of environmental affairs for the San Diego County Regional Airport Authority, the agency that manages Lindbergh.
The birds had always been nesting in the mud flats in and around the airport, and near the old control tower. Because of changes caused from the renovation that included relocating the control tower, the airport was required to create an area where the birds could go, Gilb said.
Airport officials established protected areas just southeast of the runway, where the birds seem to flourish despite the noise from the din of jet engines.
“They don’t seem to mind the noise, and it seems to keep their predators away,” Gilb said.
To give the fragile terns a fighting chance, the airport contracts with the U.S. Department of Agriculture for a predator control program that includes setting traps for some of the more aggressive enemies.
“They caught a hawk this year in one of the traps,” Gilb said. The captured birds and other predators are delivered to nonprofit wildlife organizations that eventually release them far away.
The airport authority’s cost for the predator controls, along with the monitoring of the terns’ nests, is $110,000 a year.