By Janice Boussey

A huge thank you to those members that participated in the Backyard Bat Acoustic Monitoring program in partnership with the Toronto Zoo. The zoo was gracious enough to share their data and give a virtual presentation at our October meeting. They provided a good overview of bats around the world and told us a little more about our local species.

It was an exciting summer watching the data come in at each site. By sharing this information perhaps you can fall in love with bats as much as our member contributors did. One of the questions asked by the project to each contributor was “has my attitude toward bats improved” to which the most common answer was “I have always loved bats”. No scary halloween monsters here, just sweet furry little fliers sharing our outdoor spaces.

A total of 18 sites contributed data to the project spread out over the county from May until September. 

Bat Monitoring Sites

For 4 consecutive nights volunteers mounted a bat listening device at each site. 

It is specially programmed to only listen for sounds of a certain frequency range, those of the bats. Needless to say we did not record all your backyard secrets – only the ones that the bats told

So what did they tell us?

Essex County Essex County Field Naturalists recorded 26,663 observations containing 7 of the 8 possible species! That’s a lot of bats.

Our Ontario bat species consist of big brown bat, eastern red bat, hoary bat, silver haired bat, little brown myotis, northern myotis, tri-colored bat and eastern small footed myotis. Only the big brown bat is not listed as endangered.

Data from each site was collected and uploaded to theToronto zoo. The zoo used a computer program to analyze the data from each site to get the initial results. They will be doing human verification of the data over the next little while. This will allow them to check for any errors or anomalies.

How did this region compare with other groups? 

3 other groups in Ontario also contributed data to the project. Our numbers trended very similarly to the other groups, with large numbers of big brown bats followed by smaller numbers of the other possible species.

Total species observations for each volunteer group. Species newly listed as endangered in 2025 are highlighted in yellow, species remaining listed as endangered are highlighted in red.

Big brown bats have adapted to live in urban areas more readily than those of it’s cousins. If you have bats in your attic, chances are they are big brown bats. It is no surprise then that big brown bats have higher population levels represented as a result

No recordings were found of the eastern small footed myotis in Essex County. This compares with the low numbers of this species by the other groups.

Where were these bats hanging around?

In your yards, of course! And also your pools, golf courses and out in the forests and farmlands. 

The monitoring sites were all on private property. Some sites were closer to homes and human activity than others. A wide variety of sites were used, in both urban areas and rural areas. What they had in common was that bats were found at every site. Many people may not realize that when the sun goes down and those bonfires get lit that you have guests arriving from above to join the party. Bats are just as likely to be hanging around your yard in the city as they are out in the county.

In fact 4 species were located at every single site (big brown, eastern red, hoary and silver haired). 6 sites recorded 5 species and 4 sites recorded 6. None of our sites had 7 or 8 species. All of these sites were spread evenly around the county. It mattered little if you were in a subdivision or out in the open or if you were in Windsor, Amherstburg or Kingsville, bats are all around us.

Bat Awards

These sites earned our “bat awards” because of the interesting observations they brought to light. Prizes consisted only of greater knowledge and understanding of our local bats. 

Small But Mighty Award- Tecumseh near Blue Heron Pond. This site recorded the lowest overall number of bats with 67. Not bad for a very new subdivision in a very urbanized area. However this site also recorded a tri-colored bat which was not detected in some of the sites with large numbers of bats.

Twins Award – Amherstburg – 2 sites were located quite close together although separated by a very busy road. Both in quite well developed subdivisions, one near a golf course, the other close to a pond and farm land. The golf course side had almost double the number of bats 1,576 compared to 690 across the street. The side with the lower number had 5 species while the other side had only 4. This shows that even sites close together can have very different populations and that more bats doesn’t always equal more species present.

Gimme Shelter Award- Staples – Some threats to bats are windmills and light pollution from greenhouses. That didn’t stop this site from attracting 6 species while being surrounded by both. A modest treed yard with a swimming pool gave the bats what they needed to hide from threats all around them here.

Bountiful Batty Award – LaSalle near brunet park – This site came in with huge numbers with the overall largest amount of bats detected at 8,018. 6 species were found here, only missing the small footed and northern myotis.

In Conclusion

Bats are often misunderstood. Studies like this help spread the word about how amazing bats really are. 

When you are out at night, take a moment to look up. You may be missing out on our other winged friends.

Janice Boussey