Once you know what to look for, you might catch glimpses of California’s native bats, even around cities like Berkeley. I see bats near Tilden Park, flittering off into the dusk like tiny airborne scraps of leather. Others notice their pointy silhouettes in the light of the moon, sunset-painted sky, pond reflections, streetlights.
Field biologist Emilie Strauss holds fond memories of watching colonies of bats, fifteen years ago, when they flew out of exit holes in structures in and around UC Berkeley. One of their homes, fittingly, was the Life Sciences Building.
These days, fourteen different species of bat (including three California Species of Special Concern) are thought to live in and/or migrate through Berkeley, according to Cat Taylor, naturalist and bat expert from the East Bay Regional Park District. That’s about 60 percent of California’s native bat species.
All of our local bats eat nothing but insects and other crawlies. Some even specialize in hunting wasps and yellowjackets.
The pallid bat (shown above and left) flies low to the ground, pouncing on beetles, crickets, potato bugs, centipedes, even scorpions. Its large sensitive ears can detect the footsteps of a cricket from 16 feet away!
The Mexican free-tailed bat (shown below) flaps as high as 10,000 feet into the night’s sky to feast on moths. It also munches mosquitoes, especially in the spring, before big, juicy moths take to the air.
Many of the insects that our city’s bats eat are, in fact, agricultural crop pests as well. “Researchers have estimated that bats save U.S. farmers an estimated 22.9 billion dollars annually,” says Dave Waldien, Co-Director of Programs for Bat Conservation International. This hankering for bugs, he adds, “is a great reason to work together to conserve our amazing bats.”
Indeed, Joseph Grinnell (1877-1939) — famed first director of UC Berkeley’s Museum of Vertebrate Zoology and pioneering California field biologist — wrote enthusiastically about bats a full century ago. In his article, “Bats as Desirable Citizens” (Pacific Rural Press, vol. 85, no. 11, 15 March, 1913), he asked human citizens for compassion.
Bats, he wrote, are “as deserving of just as much consideration as the most beneficent of birds.” They do the same bug-devouring work as sunshine-loving warblers, swallows, and sparrows, he explained. Only, bats take the night shift.
This time of year, many, but not all bats migrate south to warmer and buggier habitats. Bats in Southern California may wing their way into Mexico. Others, like the seldom scene hoary bat (shown below), visit our own area from the north.
Scientists are now learning that bats also migrate laterally, in the east-west direction. Coastal areas, like Berkeley, seem to provide them with a respite from the hard freezes in the Central Valley, according to Corky Quirk, founder of the Davis-based rescue and education group, Northern California Bats (NorCalBats).
By summer, bats will return to their regular haunts, flying and feeding by night, clinging to elusive shady gaps (as narrow as one inch!) by day. Some of these furry nocturnes will snuggle into tree bark and rock crevices. Others will hang out in Spanish roof tiles and wooden rafters — free rent for those that keep their feet up, chins down.
Summer is busy, buggy bat season
Check back later with NorCalBats and the East Bay Regional Park District for fun bat activities for the family.
Bat species list
The following native bats are thought to live in and/or migrate through Berkeley:
California Bat: Myotis californicus
Fringe Bat (aka Fringe-Tailed Bat) – Myotis thysanodes
Little Brown Bat – Myotis lucifugus
Long-eared Bat – Myrotis evotis
Yuma Myotis – Myotis yumanensis
Mexican Free-tailed Bat – Tadarida basiliensis
Greater Bonneted Bat (formerly called the Greater Mastiff) – Eumops perotis
Western Red Bat – Lasiurus blossevillii (California Species of Special Concern)
Hoary Bat – Lasiurus cinereus
Canyon Bat – Parastrellus Hesperus
Silver-Haired Bat – Lasionycteris noctivagans
Big Brown Bat – Eptesicus fuscus
Pallid Bat – Antrozous pallidus (California Species of Special Concern)
Townsend’s Big-Eared Bat – Corynirhinus townsendii (California Species of Special Concern)
How to help native bats
• Go organic: pesticides can transfer from bugs to the bats that eat them.
• Protect old trees, caves, and other natural roosting spots.
• Avoid trimming or removing trees during June through August (bat pupping season).
• Keep pet cats indoors, where they cannot kill or injure native bats.
• Consider building or buying a bat house! For more information and plans, visit Bat Conservation International
• And, if you must remove unwanted bats from your home or workplace, please do so humanely.
Bats carry rabies at a rate of about 1 in 1,000, similar to other mammals. A bat on the ground is probably sick, injured, or orphaned, and has an increased, 1 in 10 chance of having rabies. To help a bat in distress, please contact a rescue group.
Notes on photographs
All the bats pictured in this article are disabled, non-releasable wild animals, rescued by NorCalBats. Under the leadership of Corky Quirk, the group works to rehabilitate between 50 and 200 bats-in-need per year. About 40% of these animals recuperate and enjoy release back to their natural habitats.
Wearing her bat-handling gloves, Quirk carefully presented her small bevy of “education bats,” one-by-one, for the photo shoot (no flash, of course) in my kitchen-turned-photo-studio. Each species took to the experience with completely different flair.
Outside her carrier, the elusive hoary bat immediately fell asleep. This made for dozens of photos that, for lack of kinder phrasing, looked not so alive. Finally, she woke up, just long enough to say, “Goodnight.”
The tiny Mexican free-tailed bat, on the other hand (wing?), could barely stop running! A light touch on the back seemed to slow him down.
The pallid bat showed the most interest in posing for shots. In fact, he appeared to echolocate with the camera. As the shutter clicked, so did he, raising his ears like radar dishes receiving signal.
What would it be like to have a bat’s sense of hearing? In his article, Joseph Grinnell may have answered the question: “…the droning of a June beetle must sound to the bat as penetrating as the roar of a bi-plane motor does to us.”
Special thanks to: Dave Waldien (Bat Conservation International), Corky Quirk (NorCalBats), Cat Taylor (East Bay Regional Parks District), Emilie Strauss, John Greenleigh (Flipside Studios), and Rusty Scalf, local expert on the winged and wonderful.
Elaine Miller Bond is the author/illustrator of Affimals: Affirmations + Animals and the newly published Dream Affimals, from Sunstone Press. She is also the photographer for the upcoming book, The Utah Prairie Dog.
Read more about wildlife in Berkeley on Berkeleyside.
In a Berkeley park a bluebird displays unusual behavior (08.05.13)
Lynxes of the bird world: Cooper’s hawks nest in Berkeley (04.18.13)
The mystery and thrill: Shorebirds enjoy winter in Berkeley (03.21.13)
Sitting on the dock of the bay: Birds throng Berkeley pier 02.28.13)
Rare bluebird sightings bring happiness in a Berkeley park (08.07.12)
In Tilden Park’s Jewel Lake: Spotting a rare river otter (04.05.12)
Up close with Berkeley’s wildlife at Tilden Regional Park (03.06.12)
View all of Miller-Bond’s nature articles written especially for Berkeleyside.