A pallid bat flying in the night.
A pallid bat flying in the night.
(Via Michael Durham / Minden Pictures)

With bat baby season upon us, UCSC prof explains how to spot them and why they matter

Bats have come back to the Bay Area from winter migrations and are raising young all around the region. Winifred Frick, chief scientist at Bat Conservation International and an ecology and evolutionary biology research professor at UC Santa Cruz, tells Lookout how and where to find bats — and when you might catch a glimpse of a baby bat getting a flying lesson.

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Bat season is in full swing in the San Francisco Bay Area and Central Coast, which means Winifred Frick, chief scientist at Bat Conservation International, is busy.

As part of her job, Frick, who is also a UC Santa Cruz professor of ecology and evolutionary biology, sets out “bat detectors” across Santa Cruz County to see where bats are and how their populations are doing. She’s gearing up to do that now, although the locations are secret.

Frick has her “bat lab” at UC Santa Cruz, but her work takes her around the world in efforts to protect and explore the wondrous — and increasingly endangered — world of bats. She has studied nectar-drinking bats in Mexico and helped discover a new species, Myotis nimbaensis, in West Africa.

Frick is world-renowned for her research on white-nose syndrome, a deadly fungal disease that has killed more than 5.5 million bats in North America.

But luckily, she says, our Bay Area and Central Coast bats don’t sleep long enough during hibernation season for the fungus to form.

At least not yet. “We’re in a mindset of hope for the best, but plan for the worst,” she says.

Like birds, bats are tiny creatures that fly long distances, up to 200 miles. They inhabit every continent except Antarctica. And while there are over 1,400 known species (45 in North America), we have only 16 types locally.

That’s still a lot. But spotting them on the Central Coast often involves knowing where to look — and what they look like.

One of the country’s tiniest bats, little California myotis has a body size not much bigger than a thumb, making them tricky to find. Big brown bats — whose chunky bodies are smaller than a hamster, despite their name — wedge themselves into tree bark and eves of buildings. Some species, like Mexican free-tailed bats — which fly up to 99 mph, making it the fastest land animal in the world — hunker down during the day and even hibernate in caves and abandoned buildings.

Throughout May and June, migratory species like the big hoary bat flew back from their winter vacations in Southern California. So now they are all here for the season.

To find them, Frick suggests a little tech trick. She shares it in our interview below.

Frick, who has published more than 120 research papers on bats, thinks about bats all year round, not just now, during their active season. They’re also deeply entrenched in her personal life. Frick met her husband — a fellow bat nerd who is an environmental consultant specializing in bats — when she was finishing up her undergraduate years at UCSC, where she majored in environmental studies. She then got a Ph.D. in ecology at Oregon State University.

During her pregnancy in 2009, Frick felt a new appreciation for bats as “supermoms.” She watched in amazement as pregnant mama bats flew around carrying an extra one-third of their body weight in their bellies.

Go out and find a pond and watch and see if you can see a bat at sunset, and that will give you your healthy boost of wonder.

— Winifred Frick

She insists that bats have an unfair media reputation.

Contrary to Halloween horror tales of blood-sucking, virus-plagued killers, bats, she says, offer many benefits to humans. Bug-eating bats — like all of our species here in Santa Cruz County — save U.S. agriculture billions of dollars a year in pest management, and fewer pests means fewer pesticides. Bats eat their body weight in insects every night, ingesting up to 1,200 mosquitoes per hour.

While no species of bats in California is listed as endangered, experts warn that 52% of bat species in North America are at severe risk of population decline.

And California bats do face risks.

Long-term stressors like climate and land-use change are slowly wearing out bat populations. Wind turbines, which are popping up across migratory paths like through the Altamont Pass in the East Bay, are also adding dangers.

Fresh from her bike ride through UCSC’s foggy coastal campus, Frick sat down with Lookout to talk facts on our local bats.

This interview has been edited for clarity and length.

UC Santa Cruz professor Winifred Frick holding a fish-eating bat in Baja, Mexico.
UC Santa Cruz professor Winifred Frick holding a fish-eating bat in Baja, Mexico.
(Via Richard Jackson / Bat Conservation International)

Lookout: When can people see bats in the Bay Area?

Winifred Frick: I’d say the best time of year would be May, June and July. And July, August and September is when the young start flying.

Lookout: Wait, tell me about bat babies!

Frick: Bat babies are called pups. And bats in our area typically have one pup per year. So even though bats are small-body mammals, and sometimes we think of small-body mammals having lots of babies like mice or something, but bats are their own group of mammals — they’re more closely related to us than they are to rodents. And because bats are the only mammals that can fly, they can really only have one pup per year because they get pregnant. So when I was pregnant, I had so much more appreciation for bats and the idea of trying to fly when you’re pregnant.

Bat babies are relatively large compared to their [mother’s] body size. And then they nurse them for a long time because they’re making a big investment in their one pup per year. And so they’ll nurse them until pups are about the same size as a teenager. So they’re super impressive. I think of bats as being like supermoms.

So females will group up together in the summer, and they form what we call maternity colonies. And they tend to all kind of give birth around the same time so that they can all be sharing the whole birth experience and nursing. And sometimes they’ll leave a babysitter with the colony when they go out and forage. They’ll take turns and leave the young behind while they each go out.

Lookout: You say bats hang out in trees and abandoned buildings in the Bay Area and Central Coast, so how can you see them?

Frick: So you can actually get these little bat detectors that now can fit into your phone. They’re made by a company called Wildlife Acoustics and they’re called an Echo Meter Touch. It’s just this tiny little device that plugs into your phone. And then it’ll pick up the echolocation calls and display it on the screen for you. And then give you its best guess of what species. So that can be kind of fun, because if you go out somewhere, you may not be aware this fast. But if you have one of those you can hear them go by and then if you look up you can often see them.

Lookout: Can you see a bat migration like birds or butterflies?

Frick: Well, it’s at night. But there are stories that you used to be able to see the sky filled with red bats, the same as those stories of the sky filled with waterfowl. You can see it on the Doppler radar in certain places. So like in Texas, you can actually see these blooms of bats come up out of the caves and out of the bridges. You can see Yolo Causeway [a viaduct on Interstate 80 connecting Davis and West Sacramento] on the radar, too. So that’s neat. You can even do a little bat forecast with the weather radar.

Doppler weather radar stations can detect “bioscatter,” which are animals aloft in the aerosphere. Bats that emerge en masse, such as Mexican free-tailed bats in Texas, are easily detectable by Doppler radar stations. Here in California, the Mexican free-tailed bat colony that emerges from the Yolo Causeway bridge is also detectable by radar. Meteorologists often filter out these biological “clutter” when making storm forecasts, but the raw radar images have lots of biological information about animals moving through the airspace — birds, bats, and insects.

Bats emerging from under the Yolo Causeway, between Sacramento and Davis.

Lookout: I’ve read Yolo Causeway has one of the largest colonies of Mexican free-tailed bats in California. Is that right?

Frick: Definitely. They do an annual bat count there in the summer. They get a bunch of people together, and they go, and you can actually see the bats underneath the crevices of the bridge. People will count them and then they tally all that up. Then you can watch them all emerge. So it’s pretty neat. Mexican free-tails are cool that way because they usually form such big colonies and then they come out before dark, so you can really watch them and appreciate them.

Lookout: What is your favorite bat?

Frick: My favorite bat of all time is the pallid bat, which is super cool.

Pallid bats are intrepid. Firstly, they score serious bold points for eating scorpions and being immune to their venom. Secondly, where I’ve studied them in the Sonoran desert on the Baja California peninsula, they slurp cactus nectar and pollinate cactus flowers by “putting their whole selves in,” when they plunge face, ears and torso into the cactus flower to get to the nectar and dousing themselves in pollen — making them excellent pollinators. Lastly, I love that they smell a little skunky.

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Pallid bats also have really big ears and really sensitive hearing. And so they do what we call passive listening.

In addition to echolocation, they will also just listen for the sounds of their prey, scurrying along on the ground. So things like crickets and big ground beetles or scorpions, and the little scratches they make as they walk along the ground, they’ll be listening for that and then they’ll pounce down on them.

Lookout: I heard they’ve been suggested as California’s state bat. What’s your take on that?

Frick: I wrote a letter of support for that! Let’s hope it happens. That would be amazing.

Lookout: What would that do for the species?

Frick: I think it just highlights it. I mean, I don’t think it would give any additional protection. But I think it just kind of highlights and sort of showcases the importance of bats to California. And yeah, I don’t think we don’t currently have a state bat. So it’d be fun to have a state bat.

Lookout: What would we lose if we see a serious decline in bats?

Frick: There’s a lot of work going on understanding aspects of bats’ immune systems, to try to better understand our own immune systems and thinking about the ways in which that information could be used to create medical innovations and therapeutics. And then it’s been estimated bats provide billions every year to the U.S. agricultural industry in terms of the amount of insects that they consume, and specifically insects that are agricultural pests. So if we see major declines in our bat populations, we worry that we’d need to put more pesticides on.

Then there’s just the tragedy of losing our biodiversity, right? Losing the species that have incredible value to us in terms of being sources of inspiration in lots of different ways. And people may not think about it, but without bats, we wouldn’t have Batman!

Lookout: What’s a common misconception about bats?

Frick: So one of the common myths about bats is that bats are blind. They’re actually not. Their eyesight is pretty equivalent to ours. But they’re hunting at night. And our eyes wouldn’t be very good at finding insects out of the night sky to feed on, so they’re using sound and hearing to perceive their environment.

One of the cool things about bats and hearing is that they have super-sensitive hearing because they’re listening for the bounce-back of echoes, but they’ve got to blast out really loud sound so that sound can travel and then bounce back off some kind of insect. So if you think about that, they’re emitting really loud-decibel sound, but then they have super-sensitive hearing.

So they have the potential of deafening themselves, right? So they have the fastest-acting mammalian muscle that we know about. It actually dislocates their ears for the fraction of a second that they emit their echolocation call and then instantly relocates their ear so that they can hear that echolocation return. So they basically can disconnect their ears so that they’re momentarily deaf so that they don’t hurt their ears when they’re emitting sound.

Lookout: I know most of your research is out of the area, but I’ve heard you help count bat populations locally — tell me about that.

Frick: Bat Conservation International coordinates the PacWest Hub for the North American Bat Monitoring Program and I supervise that coordination/effort. The North American Bat Monitoring Program is a continental-scale effort that uses multiple sources of data, including acoustic recordings of bat echolocations during summer months, to estimate the habitat occupancy and population status and trends.

In California, we contribute by collecting data in priority areas and help other contributors collect and process data so it can be contributed to the monitoring program.

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I personally help in Santa Cruz County. I set out bat detectors once a year in locations in the county. I don’t have permission to share those exact locations.

We put out ultrasonic acoustic detectors each summer for about a week to record bat echolocations and then the data get processed to identify what species were detected.

Lookout: What else do you want people to know about bats in the Bay?

Frick: There’s some research that sense of wonder is actually really beneficial to our human health, and that there’s like recommendations of people going out and finding something to feel inspired and awed by, and so I would say that bats are always a sense of wonder. They’re so unusual, and they’re so outside our normal day-to-day lives, and yet we share space with them, and they’re out there providing benefit to us. Go out and find a pond and watch and see if you can see a bat at sunset, and that will give you your healthy boost of wonder.

Roxanne Hoorn is a June 2023 graduate of UC Santa Cruz’s science communication graduate program. Informed by her bachelor’s degree in ecology and years of experience in research and policy, she covers topics from conservation and land rights to the inner worlds of miraculous plants and animals. She hopes to engage readers in the science of their everyday lives. She produced this piece as part of UCSC professor and Lookout Community Voices editor Jody K. Biehl’s class.