A little bit about bats
Our flying mammalian friends get a bad rap from a few bloodsuckers. Yes, vampire bats are real and, yes, they have been known to occasionally nip a human. There are three blood-feeding bats among some 1,240 bat species, so bloodsuckers only account for 0.2% of bat species. In contrast, 70% of bats subsist entirely on insects. Although rodents are in the lead as the most species-rich group of mammals, bats are close behind – one out of every five mammal species is a bat.
The bat, or flittermouse as it was once called, is unique among mammals in that it is the only mammal capable of sustained flight. Flying squirrels and other mammals with baggy flaps can be impressive gliders, but they can’t hold a candle to the flying abilities of the bat.
Not only can bats fly, but they can navigate and hunt in a lightless, three-dimensional environment without the use of their eyes. Contrary to popular belief, bats are not blind. They actually have pretty good vision, but it isn’t their major sense. They rely heavily upon sound, which is evident by their oversized ears.
Bats can map out an area using sound, an ability called echolocation. They emit sounds at frequencies that are too high for us to hear. They send out ultrasounds, or high-pitched chirps, and listen for the echoes bouncing off objects and prey. They put this information together to “see” in the dark.
Bats serve several functions: some pollinate flowers, others eat fruit and disperse seeds, but most eat bugs. With a small body and high metabolism, bats need to eat a considerable number of insects to survive. A single bat can consume between 2,000 to 6,000 insects in one night’s time. The University of Florida has a bat house at their Gainesville campus that is estimated to have 300,000 bats roosting in it. Assuming an average catch of 4,000 bugs per night per bat, the colony at the University of Florida consumes over one billion insects every night. The University must have great confidence in the hunting capabilities of their bats, as their approximation is even higher than my moderate estimate – they say that their bats eat 2.5 billion insects every night, the equivalent of 2,500 pounds of bugs. In either case, those are impressive numbers.
Bats are not specialists, and they will eat just about any bug that flies. They favor beetles, moths, and flies. Unfortunately, bats don’t prefer mosquitoes. A sampling of bat guts showed that mosquitoes make up only a small portion of their meals. Still, though, bats do consume some mosquitoes as well as many other bugs which cause annoyance to homeowners and damage to agricultural crops.
Just having bats around may discourage nocturnal insects from staying in an area. Some night-flying insects can hear the chirps of bats and avoid areas where bats are patrolling.
Bats in decline
Bats are facing some tough problems, one of which is white-nose syndrome. The syndrome is caused by a fungus which manifests itself as white fuzz on the face of bats. The fungus is cold-tolerant and thrives in the cool settings in which bats hibernate. The infection disrupts hibernation, causing bats to awaken early and reducing their chances of surviving the winter. In the eastern United States, more than 5.7 million bats have perished because of this disease. In some colonies, 90 to 100% of the bats die.
How can you help bats?
One of the easiest ways to help bats is to build (or buy) a bat house. The internet is a great and wonderful place to find plans on how to build your own or get reviews on which pre-made houses are the best for attracting bats.
If bats are roosting in your attic, be responsible in removing and excluding them from your home. Have a professional handle your bats. Bats are protected animals, and fumigants and toxicants should never be used on them. Depending on your state’s laws, you may not be able to evict bats from your attic if they are established enough to have babies – you’ll have to wait until the breeding season is over to exclude them.
Bat house resources
University of Florida: Effective Bat Houses for Florida (http://edis.ifas.ufl.edu/uw290)
Bat Conservation International: A List of Certified Bat House Vendors (http://www.batcon.org/resources/getting-involved/bat-houses/bat-house-buy)
1. USDA, US Forest Service. Bat Appreciation Day 2015. Link: https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprd3835177.pdf. Accessed March 2017.
2. Ober, Holly. Insect Pest Management Services Provided by Bats, University of Florida. Link: http://edis.ifas.ufl.edu/uw289. Accessed March 2017.