Mexican free-tailed bats (Tadarida brasiliensis) Photo Credit: Charles Melton, Courtesy of WildBirdsUnlimited, Erie, PA (erie.wbu.com)
“In the end, our society will be defined not only by what we create, but by what we refuse to destroy.” –John C. Sawhill (1936-2000), president, The Nature Conservancy, 1990-2000
I walk to where the old wooden bridge used to be. I stop to watch the creek. It is barely moving. This being June, I did not expect it to be running, not in So Cal with no rain. I watch it anyway for any critter creekside activities, and I muse about the bats that live under the bridge. I wonder how they are doing.
Some years back (1998), there was a big County project to replace the wooden bridge with a cement one. The bridge was 70 years old and bats had lived peacefully there for decades. “But what about the bats?” cried one concerned citizen during a meeting about the proposed project. Thank goodness for my concerned neighbors, for the County was totally ignorant of the bats’ existence.
Officials put their heads together as to the bat issue. Their plan was to attach wooden “bat crevices” underneath the cement bridge, sort of critter condos. A bat census was taken with biologists taking the lead and volunteers selected to keep count of the bats. The volunteers were outfitted with “Tally Wackers” (a clicker for counting quickly with your thumb). The bat counters have to be very fast, as the bats come out at you all at once! Bats are very sensitive to noise and won’t fly if they think humans are watching them, so the census takers had to keep very still.
Anatomy of a Bat, Courtesy of: FalconServices.com
Besides taking the census, biologists also came back to study the Topanga bats with a device called an “anabat,” which records bat calls and is used to differentiate them. They recorded (9) different bat species. The (3) main ones were the Big Brown Bat (Eptesicus fuscus), the Little Brown Bat (Myotis lucifugus) and the Mexican free-tailed bat (Tadarida brasiliensis), with the latter being the most common under the bridge. They also discovered (2) environmentally sensitive species: the Pallid Bat (Antrozous pallidous) and the Western mastiff bat (Eumops perotis).
Listen to Bat Calls Courtesy of Cornell Lab of Ornithology
Everyone was abuzz with questions about bats. The Elementary School did their part to educate and satisfy the curiosity of all the Topanga kids. I guess all went well, though I am sure the bats would rather have the old wooden bridge back.
For my part, I learned that some bridges are used as roosts by male & juvenile bats, while other bridges contain roosts for nursing- maternity roosts, if you will. Besides bridges, bats could also roost in caves or tree hollows. The maternity period is from June to August. I don’t think our Topanga bridge was just a maternity roost, because many hundreds of bats lived there.
Bats are very helpful in the ecosystem. As they are the only mammal capable of sustained flight, they are important pollinators, seed dispersers and insectivores. They can eat over 600 insects each day! Perhaps the bats at the bridge are the reason we Topangans can sit by the creek on a summer’s night and not get bitten by mosquitoes!
Little Brown Bat (Myotis lucifugus) BLM/Photo By Adam Mann
Flying about catching bugs requires lots of energy (more than 1,000 heart beats per minute!) So bats need lots of rest. Bats can lower their body temperature and metabolic activity in a process called torpor. Torpor can last for a few hours or several months. Deep, long-term torpor in winter is called hibernation. Periods of torpor are spent in a roost, protected from extreme temperature and predators.
Bats can be found near homes with bug-attracting lights and ponds. If you have bats in your attic or under your roof, they are probably dayroosting, having found a warm, protected place to rest during the day while digesting a meal. They may even be using your attic for a maternity roost. Note: If you are trying to remove bats from your house, it is important to wait until Fall for the nursing period to be over.
In their role as pollinators, nectar-feeding bats are important to desert ecosystems of the Southwest because they pollinate cactus, such as the Giant Cacti of Arizona, and the Agave plants. Tequila lovers should thank the bats next time they sit down to a Margarita!
Bat population is diminishing worldwide. In California, 10 of our 24 bat species are currently classified as “Species of Special Concern,” meaning that they require active management to prevent them from becoming threatened or endangered species. California’s population growth has decreased the amount of available bat habitat. Disturbance and pesticides at bat colony sites (caves, mines, buildings, and bridges) have had serious adverse effects on bat populations.
As I stand down at the creek, I wonder if our bats have suffered any from noise & traffic since the new bridge was constructed. Just how are they doing in their new condos?
Do you have bats living nearby? We’d love to hear about them.
For more information on bats, building bat houses or to join the effort in conserving bat populations contact:
Bat Conservation International
P.O. Box 162603
Austin, TX 78716
© 2012, Kathy Vilim. All rights reserved. This article is the property of BeautifulWildlifeGarden.com If you are reading this at another site, please report that to us
About Kathy Vilim
We have bats. I enjoy watching they flit here and there in the evening sky. I don’t know where they live. Bats don’t get rid of all the mosquitoes that live in our wetland but I am happy they get the food they need.
Mary Pellerito recently posted..Creating Self-sufficient Gardens
Happy to hear you enjoy the bats, too. Living in a wetland area you likely have way more mosquitoes than we have.. enough to feed more bats. Maybe you will find their roost. It could be in a tree hollow or cave.
Kathy Vilim recently posted..California’s White Sage of the Chaparral
We live less than a mile from the Mississippi River Gorge in the city of Minneapolis. About 15 years ago, community and river organizations began offering grants to encourage the use of native plants in our gardens. The goal was to provide food and habitat for residential and migrating birds along the river gorge. One evening last summer, just at the sun had set, we were treated to at least 50 bats swirling just over the tree tops, diving at 30 or so dragon flies. Fascinating to see such a beautiful dance in the sky. Often wonder if they would have been there without all the native plants in our urban community.
That scene sounds wonderful! To see a whole flock of bats at sunset on a summer’s eve, must have been so special. I am sure the native plantings helped by providing more insects. How nice that your community is so forward thinking~ Thanks for sharing!
Kathy Vilim recently posted..California’s White Sage of the Chaparral
There are bats of some variety in the yard in the evening—probably big browns, but they move too quickly to be sure. I’ve never figured out where they roost. There are no shortage of dead trees that might provide roosting hollows in the area (and they’re not in the attic!) I’d love to put up a bat house, but we have such an enormous range of local wasps that colonize the birdhouses, I expect I’d be creating more wasp than bat habitat!
UrsulaV recently posted..Hummingbird Fledglings!
Ursula, I am glad you have bats in your yard, too. Do you ever see them pollinate any of your native plants? I am sure they don’t need a bat house.. can’t take risks with wasps! The bats probably have their roosts all picked out~
Kathy @nativegardener recently posted..California’s White Sage of the Chaparral
I had put up a bat house following carefully the instructions on which way to face it, etc. It sat for four years before this year when it fell off the snag which wasn’t a problem…no takers (except some invasive cuban treefrogs one year). I long for the bats to come join our little wildlife paradise. I may try putting up the bat house again since I KNOW they are in the area, just not doing their thing at my house.
Loret T. Setters recently posted..Bird Brains
Good to know bats are in your area, YAY. I am sure you can get some to join your wildlife paradise. What role will they play there? I am sure you have plenty of bugs for them! But do they pollinate any native Florida plants?
Kathy Vilim recently posted..California’s White Sage of the Chaparral
We have a bat house just up since last year but still no bats…they tend to live in the woods across the street although we have 2 ponds near the bat house…in Ny the bats have sufferd greatly so I am not surprised that we have no bats…hoping for a recovery of NY bats…how wonderful to find bats and study them!
Donna Donabella recently posted..Simply The Best-June
Donna, it sounds like you are all set up with the ponds near the bat house.. But if they are happy with their current roost in the woods, they may not want to relocate. I hope you get to see them fly around some summer eve~
Kathy Vilim recently posted..California’s White Sage of the Chaparral
Bats are such mysterious little creatures, I never knew they could torpor for months at a time…am I using that word correctly? Nor that they had knees and thumbs. Anyway, I beautifully written piece, and I learned a lot; for example, I have to say “thank you!” to the bats that polinate the Agave plants because enjoying a blended, mango margharita with my sister is one of my favorite things
Bats, Bridges, and Tequila…
Hah, I knew someone would mention the bats pollinating the Agave plants sooner or later
And yes, I think its cool that bats have KNEES!
Kathy @nativegardener recently posted..California’s White Sage of the Chaparral
This is very timely as my friend passed away a year ago this month and her specialty and love was for rehabbing bats. She took two of her non-releasable bats to schools to educate and she forever changed how I felt about bats…this is a lovely post..thank you…Michelle
Rambling Woods recently posted..Here is Mama duck and her two ducklings. She is using the undamaged part of her bill to scoop up the food
Thank you, Michelle for your warm comment. I am so happy I was able to remind you of your dear friend and her special love for bats.
Kathy @nativegardener recently posted..California’s White Sage of the Chaparral
I wanted to mention that 2011-2012 is the year of the bat..and I belong to BatCon
Rambling Woods recently posted..Here is Mama duck and her two ducklings. She is using the undamaged part of her bill to scoop up the food
I love to watch the bats ascend on my garden on summer evenings just like last evening – not sure what kind as all I see are silhouettes. I have thought about putting up a bat house and will most likely do so when I have more of the garden mapped out. I always wonder where they currently roost. I know they are not in our attic but every spring and fall we seem to have a rogue bat visitor (probably a young pup) who climbs up through our double hung windows to visit our house instead of the garden for a night or two! Very exciting I’ll say.
thevioletfern recently posted..Bye Bye Barberry
That does sound exciting to have a bat visitor! Sounds like you make an agreeable hostess. If you have a forest nearby, the bat roosts are probable in tree hollows there. Hope you and your garden are handling the heat wave~ Stay safe over the holiday~
Kathy @nativegardener recently posted..California’s White Sage of the Chaparral
What a great confluence of ideas — to help the bats in the context of new construction. Thanks for posting this story. I’m enthralled by bats … always feel a sense of magic when they grace me with their silent flight.
ingrid recently posted..An Interview in Empirical Magazine
I agree with all your enthusiastic readers. Worthy of an addition to Wikipedia. Now I am over my dislike and distrust of those furry, winged creatures because of Kathy’s well researched and documented article. I will say hello to the bats whenever I pass by the bridge. JFS