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Thursday, June 26, 2008 | To find two of the county’s last burrowing owls, you will need four-wheel drive, a key to a padlocked gate and a hearty knowledge of the sage-covered wilderness near the base of Otay Mountain.
There, on rolling hills owned by the city of San Diego, two of the tiny birds have made their homes in man-made burrows in the ground — sections of buried plastic pipe with rock-ringed openings at either end. But the tiny colony of artificial burrows, 23 potential owl homes in all, sits mostly empty. No other owls have found them.
In San Diego County, the once-prolific bird has mostly vanished. By the most optimistic estimates, fewer than 100 remain. The burrowing owl is the only owl species to live underground. It is one of nine owl species in San Diego, about as big as a pigeon, with brown feathers, spindly legs and piercing yellow eyes.
And it is disappearing.
Phil Unitt, curator of the San Diego Natural History Museum’s department of birds and mammals, said he believed the owl would be the county’s next species to be extirpated — eliminated locally but not extinct elsewhere. The owl, he said, is poised to meet the same fate as such birds as the California condor, fulvous whistling duck and yellow-billed cuckoo, which were all once found in San Diego County.
“It would be just one more example of humanity sweeping aside whatever is inconvenient,” Unitt said. “It just so happens that the burrowing owl is one of the more conspicuous things that we can notice.”
Across California, the tiny owl’s population has dropped precipitously in the last three decades. During the 1980s alone, 60 percent of the state’s burrowing owls disappeared. The owl’s decline in San Diego County has been starker, dropping 85 percent since the early 1980s. Today, scientists estimate that no more than 92 owls still live in San Diego.
“I think we lose more (owls) every year,” said Jeff Lincer, research director at the Wildlife Research Institute in Ramona, who has extensively studied the owl. “The protection for this particular species is not adequate. It’s not having an impact.”
Without human intervention, several biologists said the bird’s local population will likely be eliminated. While the owls still live elsewhere across the West, with a large population center in Imperial County, they’re teetering on the brink here.
The owl’s population in San Diego was not supposed to reach this point. Like many declining species in San Diego, the owl’s numbers have been reduced by human development and the resulting loss of habitat. But those conflicting interests were supposed to have been addressed in the late 1990s, when San Diego adopted a landmark plan that aimed to balance development and species protection.
The plan, known as the Multiple Species Conservation Program, established the boundaries for large habitat preserves across San Diego and offered protections to the owl and 84 other plants and animals. In return, developers were afforded a guarantee that their permitting processes would be expedited.
The habitat plan offers the owl’s most robust legal protection. The federal government has not designated the bird as endangered. State officials rejected a petition to list the owl as endangered in 2003. So it is left to the habitat plan, which calls for new construction to avoid impacting numerous species, including the owl, whenever possible.
But some biologists say the burrowing owl is slipping through the cracks of that plan, which has been lambasted by a federal judge since its adoption. And with the largest remaining population center near the proposed third U.S.-Mexico border crossing, some see dim prospects for the owl’s future.
“It’s hard to say whether the owl will persist in San Diego County,” said Jerre Stallcup, a biologist with the Encinitas-based Conservation Biology Institute, who provided the scientific research for the habitat plan. “It’s likely that it will not, just because the numbers have gotten so low. … It’s a really bad omen for the MSCP that we have so many species in this particular circumstance.”
The idea behind the habitat plan was to protect San Diego’s most biologically diverse land and allow homes and businesses to be built on less important habitat. The deal was a tradeoff for developers and environmentalists. Some valuable land wouldn’t be built on; some valuable habitat wouldn’t be saved.
“It made sense to protect [owls] in areas where they had a long-term chance for survival,” said Craig Benedetto, a spokesman for several housing developers, “and less sense to protect them in a site in the middle of industrial complex in Otay Mesa.”
Some evidence exists that the owl’s population has increased in Otay Mesa in the past decade, said Barry Jones, a senior consulting biologist for Helix Environmental Planning, a consulting firm. Those remaining birds stand to benefit from the large swaths of conserved land in the county, Jones said. “There are some areas where we are seeing some success,” he said.
The problem with the owl is that many of its remaining clusters are found on land targeted for development. And attempts at relocating the owls to conserved land have not been successful, Lincer said.
The owls are particular about their homes. Unlike most owls, they live underground, not in trees. They like grasslands, flat open spaces where ground squirrels can tunnel into the earth. When the squirrels leave, the owls move in. The grass can’t be too tall, because it exposes the birds to sneaky predators. When development happens and owls are displaced, the birds are forced to find a new home.
The birds are not found in sexy places. Their remaining habitat doesn’t have sweeping coastal vistas and rolling hills. One recent population was discovered behind a bustling truck stop.
Michael Deutsch had never heard of burrowing owls before he tried building a new 136,000-square-foot self-storage facility in Otay Mesa. After owls were found, Deutsch spent $65,000 to hire Jeff Lincer to ensure the birds weren’t around when construction started — a requirement of the habitat plan.
Lincer used that money to close off the burrows on Deutsch’s land and install a dozen artificial burrows near Otay Mountain as mitigation. But he wasn’t legally allowed to move the birds himself. State regulations prohibit trapping and transporting the owls to new sites. He was left to hope that they’d find the holes.
On a recent spring morning, Lincer unlocked a chained gate and bounced down a rutted dirt road to inspect the 23 artificial burrows in the sage-covered hills near Otay Mountain, hoping to find signs they were being inhabited. From atop a nearby ridge, two owls perched on a post, keeping an eye on Lincer’s work. But those owls had lived in the area for years, in another set of Lincer-made burrows.
Standing in the midst of an open, grassy field, Lincer poked around, looking for tell-tale clues of owls: Regurgitated food, remnants of an eaten insect, a few feathers. Even a streak of poop on a rock. But there were few signs of use. Black widow webs covered several burrows. No luck.
Lincer said that highlights one of the flaws of the habitat plan’s owl protection. Owls aren’t supposed to be killed by construction work. But Lincer said building often indirectly kills them anyway. Lincer is hired to close burrows, to ensure no owls are on site when construction starts. Because the burrows — the owls’ shelter — are eliminated, the birds are forced to fend for themselves without the refuge they once relied on. That makes them vulnerable to predators.
“In any instance where there’s been a development and it’s involved burrowing owls and mitigation to evict it, I cannot think of any evidence that it’s been successful,” Lincer said. “It’s hard to think that despite the fact that we keep killing them that the population is increasing.”
Estimates of the owl’s population have been infrequent. No estimate exists of the owl’s population before the habitat plan was adopted. Benedetto said that lack of evidence undermines claims that the plan is contributing to the bird’s decline.
“We are doing as a region what we need to protect the owl,” Benedetto said. “Unless you have evidence the bird is crashing, you can’t say the program isn’t working.”
Stallcup said biological monitoring is needed for the owl and other protected species, to ensure their populations are tracked before becoming so low. The habitat plan included a promise that a pool of money would be created for such tasks, but it has never been fulfilled. The San Diego Association of Governments plans a 2010 ballot initiative to address that, but the details and funding sources have not been identified.