Photo: Brian Garrett/Creative Commons License

Shadowy blurs fly overhead, looping in acrobatic treble clefs across the dusk sky. Occasionally an audible sound is heard coming from these winged hunters as they gobble up thousands of insects during this aerial evening feast. That’s the dinner show I get to witness during the summer months from my Glendora backyard when the local bats return to our local skies.

But it’s not summer yet and the bats are already here!

Thirty years living in the same Glendora house and I’ve never seen so many bats this early in the year. Was this early arrival attributable to the glowing effects of a very wet winter? Or perhaps I’m just noticing a specific bat species most active during the spring within the San Gabriel Valley. Lots of questions to ponder while watching the evolving night sky. Nevertheless, I’m pleased with the idea that their early arrival may coincide with a decline in mosquito and beetle populations. Maybe…just maybe… I won’t stress as much about getting West Nile Virus. According to Bat Rescue, a single bat can consume up to 1,000 mosquitoes an hour, so imagine the damage 20 bats flying around like I saw last night could do!

Currently, seven species of bats have been identified in Glendora alone. Biologist Lauren Dorough determined in the greater range of Orange County that there are 16 species of bats from amongst the 25 species currently found in California.  A few species have adapted to the urban environment by roosting under bridges and inside abandoned buildings, environments very different from the natural environments that their bat-cestors once enjoyed. What a new, rich habitat for bats!

Even with such adaptations, it’s important to note the population of bats as a whole has been impacted significantly by disease. Bat Rescue notes 40% of American bat species are in serious decline or listed as endangered or threatened. Bat Conservation International reports in North America alone, 5.7 million bats have died from White-nose Syndrome, a disease that strikes bats while they’re hibernating. Sourced back to a New York cave, the deadly disease has caused 100% mortality rates throughout the U.S.

Besides diseases, bats have been impacted by wind turbines. The winged mammals have a propensity to collide into the fast moving blades while migrating to hunt or return to their nests. My family and I once toyed with the idea of producing electric energy and installing wind turbines within our Texas property, but we only considered its impact on birds, ignorant then of the hazard it presents to bats. I would hope others interested in wind turbines will consider bat populations nearby.

Besides controlling mosquito populations, bats also produce beneficial bat guano. Guano is the waste product produced by bats and is gathered from their caves to embellish fertilizer, create antibiotics, and detoxify wastes. Like many natural resource, bat guano has been overharvested, harming precious ecosystems that revolve around its existence. Guano itself can also contain serious diseases easily transmitted to humans. Thus, extracting bat guano without the care of trained professionals is not recommended. Bats within the San Gabriel Valley have been found with the rabies virus within the past 10 years. If you do find a bat in or around your home or property where it is unwanted, it’s highly recommended to contact a bat specialist or your local vector control for safe removal.

A lesser long-nosed bat pollinates a cross section of a saguaro cactus flower. Creative Commons photo by Merlin D. Tuttle, Bat Conservation International.

Guano may be dangerous, but bats themselves are highly beneficial. They are an important crop pollinator, spreading the pollen of peaches, almonds, dates, mangoes, and figs.  They also are exceptional at dispersing seeds that may attach to their fur or carried within their tiny mouths. Unlike bees that are daytime pollinators, bats are nighttime pollinators, and enjoy agave flowers and other twilight blooming funnel/tube-shaped flowers like Lonicera, Yucca, Nicotiana, or Datura. You may even see a bat pollinating your backyard peach tree or the native Erigeron!

Those with a concern and affinity for these important nocturnal animals can help populations by buying bat boxes and posting them high up to create a colony of bats. Planting an evening blooming garden for night time pollination can be enjoyed with the aid of a webcam equipped with night vision.

There are so many amazing things that bats do humans. Did you know that vampire bat saliva is used to produces an anticoagulant that aids stroke victims and heart patients?  Next time you’re hanging out in your backyard or a ¼ of a mile near the closest water source, pull up a chair and look into the night sky like I did. Who knows, maybe a bat will fly by, and you will know it is hard at work.

Feel free to share your bat stories…I am all ears! All joking aside, bats really do have amazing hearing. Their echolocation abilities are so sensitive they can detect targets nearly a yardstick away within a 6/1,000th of a second, so perhaps they heard and appreciated my joke. I look forward to going batty for bats right along with you.

Field Guide to Bats in the San Gabriel Mountains
Mapping the Bat Population in Southern California
Here’s to the Bats of California!
Bats In The Desert And The Southwest


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