The evenings are growing darker and the nights are getting longer. With Halloween just days away, what better time to learn a few facts about the bats of New York City? Kaitlyn Parkins, the Associate Director of Conservation & Science with New York City Audubon, is an expert on the bats of Gotham and shared some knowledge with us.

Many species of bats can be found in NYC

Parkins says all of the bats here are named after their color and are quite small in size.

“We have eastern red, silver-haired, and hoary bats which are all tree-roosting bats. And then we have big brown, tri-colored, and little brown bats which are cave-roosting bats. A little brown bat weighs only 0.29 ounces, and even our biggest bat—the hoary bat—weighs less than an ounce."

New York City: five boroughs, six tiny bats.

Eastern Red bat at the Javits Center

Courtesy of NYC Audubon

New York City bats dine on bugs

Parkins says, be glad for that. "All of the bats in New York City are insectivores, which means that they eat insects like mosquitoes and other pests. Bats in the U.S. actually save farmers billions of dollars and pest control services every year. So we want our bats around so that they can eat all of those pesky mosquitoes and other bugs that bother us."

But do they eat roaches? Parkins says, "Unfortunately for the most part NYC's bats are 'aerial hawkers,' meaning they pursue and catch insects in flight, as opposed to 'gleaning' bats that pick prey off of surfaces. They are mostly eating moths and other flying insects, but since they are generalist predators (they'll eat a lot of different kinds of insects) if a roach was, say, flying around outdoors it might make a good snack!"

Some New York City bats roost in trees

Parkins says we might have a mental image of bats as living in barns or caves or under the eaves – and some do! But not the one most common in these parts. The eastern red bat is a tree bat and spends its time hanging upside down from branches like a little dark leaf.

“Most people will walk right by many of them on street trees in their lifetimes and never know that they're walking past bats."

Nothing to see here, just a little dead leaf, hanging from this spooky tree.

Some bats hibernate, some bats migrate

Parkins says some species, like the brown and tri-colored bats, will head out of the city once the weather turns cold.

“They will find caves and they will roost in those caves over the winter. Other species—the eastern red and silver-haired and the hoary bat—are migratory bats, so you think of them as migrating the same way birds might migrate. These bats migrate south and we're at the very top edge of the winter range.”

She added, however, that "some of these bats actually spend their winters in New York City in leaf piles or under the bark of trees. And on warm days in the winter you might actually see these bats out foraging [for insects]."

Yeah, they hang out in leaf piles. Romp with caution.

New York City's bats are incredibly noisy... we just can't hear them

While it makes it easier for them to sneak up on you, Parkins kind of makes this feature sound like a good thing.

"The bats of New York City echolocate from 20 to 80 kilohertz. They are also some of the loudest animals in the world. They emmit sounds over 100 decibels, which is essentially the equivalent of a rock concert or a jet engine. But because they are echolocating at such a high frequency that we can't hear [humans can only really hear up to a maximum of 20 kilohertz] we don't hear them screaming into the night to find their insect prey."

If you want to learn even more about the secret lives of urban bats, Kaitlyn Parkins is leading a talk on the bats of Gotham at Green-Wood Cemetery, Thursday October 28th at 6 p.m., via Zoom. It costs $5.