By Rachel Delbo, CCC Intern at ACLT
Around the marshes and woods at ACLT, there are several game cameras routinely monitored by volunteers. These provide a snapshot into the behaviors and habits of wildlife in the area. Regulars seen include raccoons, foxes, and great blue herons, but this time something a little different was spotted on camera. One of our volunteers, Ian Messent, recently captured a video of a bat catching insects just above the water in the Horse Swamp Creek. You can watch this nighttime video below:
At this time of year and especially in the summer, bats are a common sight just about everywhere in the state. On most nights at dusk, they will leave their roost and take flight in search of insects. However, during the winter months, bats go into hibernation. They are only seen during this time if it is exceptionally warm, although this is rare. In those cases, the bats you are most likely to see are known as Big Brown bats, the only species in Maryland able to survive exposure to sub-freezing temperatures.
There are actually 10 species of bats in Maryland and they are divided into two groups based on their preference of shelter.
Tree bat species include:
- Eastern Red bat (Lasiurus borealis),
- Hoary bat (Lasiurus cinereus),
- Silver-haired bat (Lasionycterus noctivagans), and
- Evening bat (Nycticeius humeralis).
Cave-dwelling species include:
- Eastern small-footed bat (Myotis leibii),
- Little brown bat (Myotis lucifugus),
- Northern long-eared bat (Myotis septentrionalis),
- Indiana bat (Myotis sodalis),
- Tri-colored bat (Perimyotis subflavus), and
- Big brown bat (Eptesicus fuscus).
All of these bats belong to the order Chiroptera, a name meaning “hand-wing”. The bones in the wings of bats are evolutionarily comparable to the bones in our own hands, with a layer of webbed skin that allows them to generate lift and glide through the air.
Despite their spooky reputation, bats are highly beneficial to both humans and other species in their natural communities. Bats can consume up to one third of their body weight in insects in only half an hour and provide an estimated 3 billion dollars in pest control services for the US agricultural industry. As an added note, I’m sure we can all appreciate a few less mosquitoes flying around.
Unfortunately, all of Maryland’s bat species are listed as Species of Greatest Conservation Need in the state. Their decline in numbers is largely due to the spread of White-Nose Syndrome (WNS), a disease affecting cave bats first discovered in Maryland in 2010. You can read more about WNS on Maryland DNR’s resource website here: https://dnr.maryland.gov/wildlife/Pages/plants_wildlife/bats/nhpbatdisease.aspx
Maryland’s bats have also been impacted by habitat loss, as have bats in many other states across the country. They are protected under state and federal law, but unfortunately many bats are still killed when they venture into people’s homes looking for shelter. The Maryland Wildlife and Heritage Service offers safe wildlife control options and DNR’s Nuisance Wildlife Hotline (1-877-463-6497) can be consulted for questions about bat exclusion.
At ACLT, one of our Master Naturalists installed two bat houses in the Parkers Creek Preserve, one at Warriors Rest and another on the Goldstein Bay farm property. Although no bats have been spotted using the boxes yet, they are available for our little winged friends if needed. You can see what these boxes look like in the photos below.


Much of the information in this article has been shared from Maryland DNR’s wildlife pages and the University of Maryland Extension Home and Garden Information Center. Check out these great resources to learn even more about bats in our state. As always, thank you to all of ACLT’s members and supporters for your help in preserving wildlife habitat in Calvert County.