Depending on where you live and the time of year, your local bat community may be made up of different types of bats. Let’s meet them!
09.11.24
By Alyson Brokaw
On warm summer nights, I love sitting in my backyard at dusk, watching the neighborhood bats flit down the streets and over the nearby fields. Now that the summer solstice has come and gone, dusk has been creeping in earlier and earlier each day. For those of us in much of North America, this may also mean the start of a new school year, a transition from the hot, mugginess of summer to the crisp, coolness of autumn, and the beginning of pumpkin spice everything. But humans aren’t the only ones experiencing seasonal shifts. Bats are also in transition—young ones are learning to hunt, and others are fattening up for hibernation or migrating to warmer spots. Depending on where you live and the time of year, your local bat community may be made up of different types of bats. Let’s meet them!
Frequent Fliers
Some bats have found a way to live and love even in the most urban areas. The most common of these synanthropes (animals that have adapted to live with or near humans) is the big brown bat (Eptesicus fuscus). These 25 gram bats are widely distributed across much of North America and can be identified by their glossy brown fur, black wings, and rounded nose. Big browns roost in all sorts of places: mines, caves, barns, attics, bat houses, and even wood piles. They usually emerge just after dusk to hunt over fields and along forest edges.
The little brown bat (Myotis lucifugus)is a similar bat that can also be found sharing space with humans. Smaller than the big brown bat (~10 grams), they were once one of the most abundant bats in North America. Unfortunately, they have experienced significant population decline due to the fungal disease white-nose syndrome. Despite that, small colonies still persist throughout their range and they can be seen emerging from roosts like attics, caves, and bat houses. If you are in the western U.S., you may also spot the Yuma myotis (Myotis yumanensis),who is nearly identical to the little brown bat but has a unique echolocation call.
Come early fall, these bats leave their summer roosts and retreat to caves and mines for winter hibernation. They remain active as they try to eat as many insects as possible and fatten up before winter. If you’re lucky enough to live near a hibernation area, you may continue to see bat activity into fall, or up until the first really cold nights.
Regional Favorites
While big brown and little brown bats are geographically widespread, your common bat sightings may be more specific to where you live. Often mistaken for the big brown bat, evening bats (Nycticeius humeralis) are found mostly in the central and southeast United States. They typically roost in trees but sometimes use human-made structures too.
In the southeast and south-central U.S., one bat stands out: the Mexican free-tailed bat (Tadarida brasiliensis). These gregarious bats form the largest bat colonies in the country, including Bracken Cave in central Texas (which also happens to be the largest known bat colony in the world!). While Bracken Cave and Austin, Texas’ Congress Avenue Bat Bridge are some of the most well-known areas for spotting these high-flying bats, they are frequently found roosting in human-made structures like bridges and houses around the southern United States.
Advanced Bat Spotting
While some bats have readily adapted to urban and suburban lifestyles, others remain a little more elusive. However, if you are in the right place at the right time, you may still be lucky enough to catch these bats in action.
Eastern red bats (Lasiurus borealis) are common and widespread across much of North America, but their solitary nature can make them harder to spot. In the summer, this species can often be spotted hunting around street lights — just look for their distinctive black and red patterned wings. Most red bat populations are considered migratory, moving from inland summer habitat to more mild, coastal areas in the winter. If you hate raking leaves in the fall, you can leave them for the bats as eastern red bats will retreat under leaf litter to hibernate when temperatures drop.
If you live along the southeast or Texas coasts, you may be lucky enough to host the solitary and beautiful northern yellow bat (Lasiurus intermedius). These bats like to roost tucked in Spanish moss or palm fronds, where their yellow and tan coloring helps them blend in. Meanwhile, desert dwellers in the southwest might spot the grinning faces of the pallid bat (Antrozous pallidus). Pallid bats can sometimes be spotted roosting in patio corners or doorways at night, taking a break from hunting scorpions, crickets, centipedes, and other arthropods.
Local Legends
While most of the bats we encounter in our backyards tend to be more common or abundant species, if you live in Florida or southwest Texas you may be visited by some rare local legends.
Found only in certain areas of south Florida, including Miami, the Florida bonneted bat (Eumops floridanus) is one of the largest bats in the United States. The Florida bonneted bat is currently classified as Endangered in the United States. They like roosting in pine tree cavities, under roof shingles and in specially made bat houses. If you are near an open area like a golf course, agricultural area, or suburban neighborhood at night, listen for their short, bird-like echolocation calls, which are within human hearing range!
Meanwhile, along the border of the Rio Grande in southwest Texas and southeast New Mexico, you might spot the endangered Mexican long-nosed bat (Leptonycteris nivalis). These nectar-feeding bats cross the border each summer to give birth and feed on agave and cactus nectar. If your hummingbird feeders are mysteriously empty in the morning, these bats might be the reason! Along the rest of the Mexican-U.S. border, lesser long-nosed bats (Leptonycertis yerbabuenae) and Mexican long-tongued bats (Choeronycteris mexicana) will also visit backyard gardens and feeders during the summer months.
Backyard Bats
Over 45 species of bat can be found within the United States and Canada, so this list just scratches the surface of who you might encounter. Many species are also hard to identify from looks alone, especially when they are busy flitting above our heads at high speeds. If you’re curious, there are portable bat detectors that plug into your phone, letting you listen in on their calls. While enjoying your nighttime visitors, think about ways to make your backyard even more bat-friendly— plant bat-friendly gardens, reduce pesticide use, minimize light pollution, and keep your pet cats indoors.
