Call Out the Bat Paparazzi: These Malibuites Need Better PR
• Less-than-Elegant Creatures Are Beneficial and Not as Batty as Most of the Myths about Them
BY SUZANNE GULDIMANN
BY SUZANNE GULDIMANN
They’re quiet neighbors, as elusive and silent as ghosts. Many Malibuites don’t even know they’re here. However, at least six species of bat regularly make their home in Malibu, and now that spring is here, they're waking up and going about the business of nocturnal insect hunting, rarely seen by diurnal inhabitants and untroubled by publicity or paparazzi.
Bats have had more than their share of bad press, however, most of it undeserved, according to local bat biologist Diana Simons, who works with Caltrans to resolve bat-related issues. “People always want to know about bats and rabies. Less than one half of one percent of bats in the wild have rabies,” Simons says, adding the caveat that healthy bats are rarely seen on the ground, and that any bat found on the ground has a 10 percent chance of having the virus. “It’s a biased sample,” she says. “The best thing you can do if you find a bat on the ground is really easy: don’t go up to it.”
Simons dispels an assortment of bat myths. “Bats are not rodents,” she explains. “They belong to their own genus. One quarter of all mammals are bats. Bats are also not blind, they all can see, although some have better hearing than vision.” Simons says that the pallid bat, a local species that hunts for large terrestrial insects like crickets and scorpions, has hearing so sensitive it can detect the sound of a beetle’s footsteps. Like all local bats, the pallid bat can also use echolocation to find flying insects. The ability to use echolocation means that bats are excellent at avoiding collisions. Contrary to popular belief, bats do not fly into people’s hair.
According to Simons, prior to Irish novelist Bram Stoker’s 1897 novel “Dracula,” bats were not in the habit of associating with vampires. “Before Bram Stoker, bats were like butterflies, a whimsical little animal,” Simons says.
There are three blood-drinking species of “vampire” bat, she says, but all are tiny- the biggest has a wing span of three-to-four inches—and none live in North America. “All of our bats eat insects,” Simons explains, adding that many species can eat their own weight in insects like mosquitoes or moths every night.
A National Park Service report on the Santa Monica Mountains National Recreation Area confirms that “bat diversity is rich and varied” within the Santa Monica Mountains. The report states that at least 20 species have been confirmed in the SMMNRA. The Draft ESHA findings for the City of Malibu LCP recognize that there are “at least 12 species of bats,” occurring in the Malibu area. All 12 are considered sensitive species, and four of them are listed as endangered, or California Species of Special Concern. These include the yuma myotis, a tiny bat that makes its home near water, and the western mastiff bat, which is the largest species of bat in the Santa Monica Mountains. Both of these increasingly rare bats have been sighted in relatively undeveloped and undisturbed Trancas and Zuma canyons, as well as in Topanga Canyon, according to National Park Service biologists.
Not all of Malibu’s bats are hard to find. The Western pipistrelle, a little butterfly-sized bat that is often out before dusk, is a frequent sight on summer evenings in western Malibu, where it lives in crevices in the cliffs. Anyone driving through Malibu Canyon at dusk on a warm summer night has a good chance of spotting several species of bat, including the big brown bat, which thrives on a diet of moths and mosquitoes.
According to Simons, the Zuma area is home to a colony of as many as 500 Mexican free-tailed bats. The Mexican free-tailed bat, she says, is a fast and strong flyer that eats large numbers of what humans consider to be pest insects like moths and mosquitoes. Simons states that in humid and buggy Texas, there are colonies of this species that number nearly 20 million bats and consume an estimated 250 tons of insects per night. In arid California, the bats congregate in smaller colonies to give birth and raise their young. They often roost in attics, outbuildings and even in cracks under bridges or freeway overpasses, rather than in natural caves. Simons has seen bat colonies in what would seem to be some extremely unlikely places.
According to Simons, bats have roosted in the old wooden bridges in Topanga for decades. This habitat was lost as the old bridges were replaced with concrete. Los Angeles County Department of Public Works is now aware of the bat issue and has developed “bat friendly” alternatives.
Malibu’s bat population has the advantage of large areas of protected habitat and relatively dark skies. According to Simons, pesticides and urbanization, including habitat loss and light pollution, are a major threat to bat populations. “Most bats aren’t adaptable,” she says. “When their habitat is destroyed, they can’t just move.” Asked if athletic field lighting, like the lights planned for Malibu High School, is harmful to bats, she replies “definitely,” adding that light pollution of all types is a serious bat conservation issue.
“Light pollution from a city is not conducive to bats,” she says.
The NPS states that its biologists have identified “many key roosting and foraging areas that require protection,” but admits that there have been no studies on “the effects of urbanization and fragmentation on bat populations in [the SMMNRA].”
Many people don’t mind sharing attic space with bats, or don't even realize that they have bats for neighbors. Simons says that unwelcome bats can be humanely excluded by taping a piece of plastic over all opening used by the bats. The plastic should be taped on top and left to hang open, like a cat door flap, for at least a week. Bats will then be able to leave but not return. It is urgent, Simons says, not to attempt to exclude bats during the breeding season, which usu-ally lasts from spring until late summer.
Simons adds that some bats roost in trees or even in dead palm fronds, and that care should be taken not to trim trees during breeding season. She reiterates that all of the bat species in the Malibu area are protected species.
“If there are going to be bats in the future it will depend on the perceptions of humans,” Simons states.