Let's Go Batty for #Batweek

Many species can be found in Will County, and they play a key environmental role

Bat Week has arrived. The annual celebration of this often misunderstood animal strives to raise awareness about the more than 1,200 bat species worldwide and their pivotal role in nature.

Bats are widely considered to be nature's pesticide due to their voracious appetite for bugs, especially mosquitoes. Seventy percent of bats eat insects and one bat can consume up to 3,000 bugs in one night.

With numbers like that, some Florida officials pitched a pilot program in 2016 to use bats to help combat the spread of Zika-infected mosquitoes.

But the benefits of bats go far beyond pest control. They play a key role in pollination and distribution of seeds to maintain plants and forests. In Mexico, the Magueyero bat is closely connected to the tequila industry.

All 13 species that regularly occur in Illinois are insectivores but, outside of Illinois, there are bats that prey on small mammals, as well as fruit and nectar.

Over the summer at Hammel Woods, the public had an opportunity to get up close and personal with two types of bats that aren't found in locally: the Egyptian fruit bat and the African straw-colored bat. The goal of the presentation was to educate the public and bust some bat myths.


The creatures wowed the crowd as the presenters from Incredible Bats carried the bats around, showing off their large wingspans and offering up interesting facts. For example, the African straw-colored bat has huge cheeks for food storage and can fly up to 120 miles in search of food.

While bats can give some people the heebie-jeebies, they also can be incredibly adorable. You just need a fruit bat, some fruit and a camera to make some magic happen. 

What bats are found here?

The species that have made Illinois their home are:

  • Big brown bats
  • Hoary bats
  • Red bats
  • Silver-haired bats
  • Little brown bats
  • Tricolored bats
  • Evening bats
  • Indiana bats
  • Northern long-eared bats
  • Gray bats
  • Southeastern bats
  • Rafinesque's big-eared bat
  • Small-footed bat

Photo by Glen Buckner

What about across the District's 22,000 acres of land?

There are a number of preserves where bats can be found in Will County, especially when those preserves are located near water. While you can't see them at night when they come out to play — because the preserves close at sunset — they often can be seen during the day hanging from above.

That is, if you know where to look.

Big brown bats at Laughton Preserve (Photo by Glenn P. Knoblock)

Sometimes, the District's natural resources staff hangs out after the preserve gates close to monitor the current bat population.

One night, we did just that.

The barn at Riverview Farmstead has become a favorite spot for a number of bat species over the past few years and is one of the locations where bat monitoring takes place.

Every night at dusk, the bats emerge from the top of the barn for their bug-eating ritual, where they use echolocation to find their prey. Outside the barn, the ultrasound emitted by the bats can be recorded on an AnaBat bat detector, and the data can then be used to help identify the specific species present. 

Collecting migratory bat data

The District uses remote bat detectors at a number of preserves to monitor the migration paths of bats throughout the area. 

In the spring, these detectors were placed at Keepataw Preserve and McKinley Woods to record the sound waves emitted by the bats. Because those sounds waves are unique to each species, the data can then be analyzed to determine which types of bats are moving through the area. 

Over the course of 10 days at Keepataw, the monitors recorded 267 passes by six different species. Of those, 44 percent were from silver-haired bats. 

In six days at McKinley Woods, 92 passes from bats were recorded from five species, with 48 percent of them coming from silver-haired bats.

Photo by Chad Merda

"This data suggests that silver-haired bats are most active in the spring at both these sites," said Juanita Armstrong-Ullberg, the Forest Preserve’s natural resource land manager. "And it is known that some silver-haired bats overwinter in this region in old buildings, attics and probably in the leaf litter, similar to the red bats."

Incredible bat facts

Photo via Shutterstock

  • The gestation period for a bat is anywhere from 40 days to six months, depending on the species. But here's the real eye-popping stat: A newborn pup can weigh up to 25 percent of its mother's body weight. We'll let you do the math on what a human baby would weigh given that same ratio.
  • Most bats have only one pup a year, making them particularly vulnerable to population declines.
  • Bat guano is an extremely rich fertilizer and, prior to oil, was the biggest mineral export in Texas.
  • Bats can drink water while flying and, in slow motion, it looks wickedly cool.

Threats to the bat population

One of the big causes for concern comes from white-nose syndrome, a fungal disease that was transported by humans to the United States from Eurasia. It disrupts bats' hibernation cycle and causes them to repeatedly wake up in the winter, which burns crucial fat reserves. It eventually causes death.

So far, WNS has been found in 31 states, as well as a number of Canadian provinces.

In 2016, a bat tested positive for WNS in Washington, which was a significant finding. Previously, the farthest west a bat had been found with the disease was in Texas.

Bat Conservation International estimates that WNS has killed at least 5.7 million bats since first reaching the U.S.

Photo via Shutterstock

It's not just white-nose syndrome causing issues

Species of bats that roost in trees and migrate have been negatively affected by the increase in wind turbines across the U.S.

Scientists don't have any clear answers on why bats are attracted to wind turbines but United States Geological Survey scientists at Fort Collins Science Center have created a research program to investigate the cause.

It's also believed that pesticides are contributing to bat deaths, as high levels of organochlorine insecticides are being found in dead bats. However, there is a lack of clear scientific research to link the two.

(Photo by Michelle Blackburn)

How can I help?

There are a number of ways the public can lend a helping hand to the bat population. For example, some local Eagle Scouts recently installed bat houses at Kankakee Sands Preserve. These houses will provide a roosting habitat for a colony of big brown bats that calls the preserve home.

For those looking to do something close to their home, it's fairly easy to install a bat box in your own yard. Doing so has two benefits: Not only will it serve as a summer roosting habitat for the bats, but it will also help control those pesky mosquitoes.

While there's no guarantee you'll successfully lure bats, research shows your odds will be greatly increased if you live within 1/4 mile of water, if your house is a dark color and if the bat house will receive at least six hours or more of full sun.

Bat Conservation International also has a number of good tips and guidelines.

For bat enthusiasts, the Forest Preserve District is looking for volunteers for its new Citizen Science Bat Monitoring Program, which is part of a multiagency effort to establish a regional monitoring program in northeastern Illinois. The 2018 program will involve monitoring bats at three different preserves once volunteers have attended a mandatory training session.

(Lead image by Glenn P. Knoblock)