CHAMPAIGN, Ill. – Bats, long associated with Halloween and tales of horror, have far more to fear from humans than we do from them.
Researchers at the Illinois Natural History Survey (INHS), Prairie Research Institute, monitor bats statewide by capturing, identifying, and banding individuals in fine-meshed netting (mist nets) and collecting acoustic recordings of high-frequency bat calls. Bat numbers in Illinois have declined drastically over the past few years, particularly species that hibernate in caves through the winter, according to Steve Taylor, a conservation biologist at INHS.
The northern long-eared bat was listed as threatened in 2015 by the U.S. Fish & Wildlife Service, and Illinois researchers have documented declining populations as likely associated with the arrival of white nose syndrome (WNS), a fungal disease that spreads among bat populations. Infected bats emerge periodically from hibernation and fly, using up energy needed to survive to the end of the hibernation period. Many die from the disease.
Until this year, WNS appeared to be spreading westward from New York throughout bat populations in eastern North America. However, in 2016, an infected bat was recovered in Washington State, possibly the result of human transport of the fungus.
Bats are also threatened by wind energy farms, where they are hit by spinning turbine blades.
Bat populations grow slowly; female bats have only one or two offspring per year. However, adults can live up to 40 years, depending on the species.
“In terms of their longevity and reproductive rate, bats are more like elephants than mice,” Taylor said.
Illinois’ bats are beneficial, providing ecosystem services by eating moths, mosquitoes, and crop pests. But we are only beginning to understand details of their diets. In the past, scientists have looked for fragments of insects in feces (guano) under a microscope to attempt to identify prey.
Matt Niemiller, a scientist working in the INHS Ecological Genetics Laboratory, is analyzing guano using environmental DNA to reveal genes of insect prey in the bat guano. If the results show corn rootworm DNA, for example, scientists know that the bats have foraged in corn fields. These studies help us understand bat behavior and habitat use.
“We are hoping that this information will tell us which microhabitats the bats are feeding in, not just what they are eating,” Taylor said. “With details of a bat diet giving us a better picture of how they use the landscape, land managers can make more informed decisions that will help these vulnerable animals survive in the face of changing land use.”
Although bats may occasionally be found in or near buildings, the myth that they attack people is not true. No blood-feeding vampire bats occur in Illinois, although vampire bats, which range from Mexico into South America, do feed on the blood of sleeping animals. They approach from the ground and make a small cut, from which they lap up the blood. Even among the vampire bats, feeding on humans is rare; feeding on livestock and birds is more typical.
Bats are also not blind, contrary to the popular saying, “blind as a bat,” said Tara Hohoff, bat survey and monitoring coordinator with the newly initiated Illinois Bat Conservation Program, http://www.illinoisbats.org/.
“They can see very well in the dark and also echolocate, allowing them to find objects using reflected sound. Using night vision to watch the nets, we typically observe many more bats flying over the nets rather than flying into them. Bats are very hard to catch,” Hohoff said.
Bats use echolocation to catch tiny insects in the dark and swoop through dense forests and in caves. They do not bump into humans and become entangled in their hair—except in the movies.
Ultrasonic acoustic monitoring of bats, conducted by the Illinois Bat Conservation Program, and by researchers conducting environmental research for the Illinois Tollway, provides additional data about habitat use throughout Illinois. Hohoff uses the distinctive characteristics of bat calls to identify the bat species occurring in different areas and habitats throughout Illinois.
Media contact: Steve Taylor, (217) 714-2871, firstname.lastname@example.org