What gives with the seeming bat boom?
It’s the time of year when people start seeing more bats, when more bats get into their houses, when more bats are submitted for rabies testing.
It’s a new generation of bats, testing their wings.
“This is the time of year when young bats are learning how to fly,” said Jenny Dickson, director of the state Department of Energy and Environmental Protection’s Wildlife Division.
“Everyone leaves the roost and goes one way, the dumb kid goes the other way,” into someone’s house. “It’s pretty common,” she said.
While we may be seeing more bats now, the population has not rebounded from the devastating whitenose syndrome, which has killed millions of bats since it was first found in 2007 in bats in a cave near Albany, N.Y.
“Even if we could wave a magic wand and get rid of white-nose tomorrow, it would be decades before we could rebuild the population,” Dickson said.
While bats are more prey than predator, “bats get a bad rap; there’s no two ways about it,” Dickson said.
They can carry rabies. Since it is fatal if not treated, rabies is a pretty frightening disease. Bats also are suspected of being the source of the coronavirus that began the COVID-19 pandemic.
But while there are a lot more bats flying around now — eating millions of mosquitoes, by the way — rabies does not pose a significant threat, Dickson said. “Less than half of one percent will have the rabies virus,” she said. And in order to catch rabies from a bat, a person would have to be bitten or scratched.
In the past year, the State Public Health Laboratory tested 459 bats submitted by the public and 15 tested positive, a rate of 3.3 percent. But those were bats submitted “that were behaving strangely in the first place,” Dickson said.
But it’s best to keep them out of the house. If one is flying around the bedroom at night, a series of rabies shots may be in order, as a precaution, experts said.
The rabies vaccine isn’t as frightening as people think either, said Laura Simon, field director for the Humane Society of the United States. It requires four shots in the arm over two weeks, plus a dose of immunoglobulin.
“It’s not painful at all and it’s 100 percent effective,” Simon said.
“Rabies is extremely low in this country” among people, Simon said. “We have one to three people die in this country every year.” That’s in large part because dogs are required to be vaccinated for rabies. “Despite how low the risk is of a person in this country contracting rabies, we go to extraordinary lengths to protect them,” she said.
In one of the most highprofile rabies cases, Greenwich teenager Maria Fareri, an eighth-grader at Central Middle School, died of rabies in 1995, after she was exposed to a rabid bat. Her family did not know she had been bitten, and she was not treated in time. Fareri became the first person to die of rabies in Connecticut since 1932.
According to the Centers for Disease Control and Prevention, there are about 5,000 animal cases of rabies in the United States each year, 90 percent in wildlife. This is a major change in the past 60 years. Back then, most cases were in domestic animals, primarily dogs, the CDC reported.
According to the state Department of Public Health, of 949 animals tested in the past year, 40 tested positive for rabies: two bobcats, three cats, two coyotes, three foxes, nine raccoons, four skunks and two groundhogs, in addition to the 15 bats.
“You never want to handle wild animals,” Dickson said. “You want to avoid interactions with them, but it’s not something that warrants a high level of concern.”
Also, the fear of being attacked by a rabid bat isn’t warranted, she said. “When bats get the rabies virus, they typically don’t get the furious form of rabies. They’ll get sick and die.”
Seeing a nocturnal animal such as a bat during daytime also isn’t necessarily reason to fear. “There are those situations … where you might see them active in the daytime,” Dickson said. If the weather has made it hard for them to get their full meal of insects at night, they might still be hunting when the sun comes up. A bat also may become tired and settle under an eave at the end of a long night.
Those bats certainly have been active at night. “They can eat something on the range of 1,000 mosquitoes in an hour or so,” Dickson said. And this has been “a really good year, weatherwise, for a lot of invertebrate species.”
It’s important for the bats to be out eating up bugs, because “they’re trying to put on weight before they go into hibernation,” Dickson said. “If you’re a little bat, you’re going to pack on a couple ounces. That’s a big deal for them.”
There are nine bat species native to Connecticut, although the population of little brown bats has been reduced by 90 percent by white-nose syndrome, according to a study in the journal Conservation Biology. Big brown bats also have seen their numbers shrink from the fungus, which grows on bats while they are hibernating.
Dickson said three species in Connecticut are considered tree-roosting bats. “They typically will fly further south, and they’ll stay active all year long,” she said. Of the rest, “some hibernate in Connecticut, some will travel to nearby states,” flying hundreds of miles. “They’re really particular about the temperature and humidity conditions,” she said.
Big brown bats, which Dickson said stay out later and “can typically take a little frost,” aren’t really that big, she said. “When we talk about those guys, we’re still taking about a wingspan of 12 inches or so but a body length of about 5,” she said.
If they get into the house, it’s because a hole has been created for them, maybe by another animal chewing through a screen. “A lot of times, people have bats in and around their homes and they don’t realize it,” Dickson said. They may be under an eave or flashing. “Bats are extremely loyal to a roost location” and may stay there for decades, she said.
If they do get in, open a door or a window, dim the lights indoors and turn on an outdoor light. That will attract insects and the insects will attract the bat. A box or blanket can help trap them. They usually can’t fly off the ground or floor. “Droppings and dark brown stains may appear near eaves and beneath entrance holes and roosts,” according to DEEP.
Further, according to DEEP: “one of the simplest techniques for solving nuisance problems is letting the bats exit on their own and then preventing their re-entry.”
Those who do appreciate bats can put up bat boxes, which are open on the bottom. “They do work if you build them right and put them in the right location,” Dickson said. That would be somewhere where there is at least four hours of sunlight during the day and in an open area, not in a tree, where predators can find them.
“Bats like to be warm during the summer months,” Dickson said. “The heat helps the young bat grow during the summer.”