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Bats Are Gardeners’ Friends

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A bat flies silently through the dark of night, then suddenly twists and strikes. Our first thought at that kind of an image is that we are in the midst of a horror movie but the real truth is far different. Though creatures of the night, bats have a profound effect on the daylight world we inhabit. American bats are truly nocturnal and many people will go through their whole life never seeing one. This deep connection with the night and stories of vampire bats (which are tiny and don’t exist in the US) have given bats a bad rap.

For farmers and gardeners, bats are truly their friends. The benefit to US agriculture is over $3.7 billion a year. Think of a nasty flying insect pest and bats eat them. At our home in the gold country, bats help make evening dining on our deck possible. Though difficult to spot as they flit through the deepening dusk, each bat can eat between half to all of its body weight every night.  For our evening on the deck that means about 4000 mosquitos each, providing us with a bite-free night.

Moths are another favorite food for bats which provides my garden with welcome relief. Some foraging species of bats, like the Myotis bat can even strike insects on trees, on the ground or from the leaves and branches of trees, making a whole other group of insect pests that don’t fly at night a target. When I think of how long it takes me to catch a single cabbage moth that feeds on my broccoli and cabbage, it gives me yet another reason to be thankful for bats.

While it is true that bats can carry many diseases, including rabies (without being affected), studying their strong immune system may provide us with new means of protection to the ever-growing number of diseases that threaten us. We are far more of a threat to them than they are to us.

The diversity of bat species is astounding. There are more than 1,100 species on earth. They range in size from a tiny bumblebee bat to flying foxes with a 6-foot wingspan. Our area has 17 to 22 species, the largest being a Western Mastiff with a 2-foot wingspan. Bats have one to two offspring a year, often having “nurseries” that tend the young. They live from six to 11 years and are not rodents (another common myth).

Truly remarkable is their ability to use echolocation to find prey. Some species hear the footsteps of insects on the ground, while others can fly up to 60 miles per hour at 1,000 wingbeats per minute. Bats are amazing and diverse creatures.

I think more about attracting bats than about myth-created fears. They need a source of open water; they swoop down and scoop up water while flying. Shelter where they will be undisturbed by predators is also needed. Bat houses are a great DIY project; there are great sites with plans on the internet. A little time online at sites like or Merlin Tuttle’s bat conservation site:, will provide a wealth of enjoyment and information.

Jim Bliss and Nancy Bliss are University of California Cooperative Extension Master Gardeners of Tuolumne County.