Bat reports in region triple amid swarming season

Officials said bats become especially active in late August through early fall.

By MEGAN TROTTER
TribLive

Bat-related reports have more than tripled compared with previous months in Allegheny County, according to infectious disease epidemiology officials, with one local pest control company reporting more than 50 bat inspections in August alone.

Bryan Fichter, owner of the animal removal company Critter Control of Pittsburgh NW, said bats are more common this time of year. Data from the county’s Infectious Disease Epidemiology Program, which operates under the county’s health department, show the county so far has received 33 bat-related reports this month.

Earlier summer months had significantly fewer bat-related reports, with only two in June and seven in July.

Officials said bats become especially active in late August through early fall because of their swarming season, a period of intense social and reproductive activity that coincides with the end of maternity season and the start of preparations for winter.

“After maternity colonies break up in early August, mothers and pups disperse. In late summer and early fall, adult bats gather in large groups to mate and scout potential winter roosts,” said Abigail Gardner, spokeswoman for Allegheny County. “This swarming behavior is visible as bats circling buildings, caves, and other shelter sites at dusk and night, often landing and crawling in and out of entry points.”

Certain bat species, such as the hoary bat and eastern red bat, are migratory and travel south in fall to warmer areas where food remains abundant. The health department said they may temporarily use attics, barns or sheds as resting spots.

Fichter said Allegheny County most often sees little brown bats and big brown bats.

Critter Control of Pittsburgh NW is a local franchise office of the national Critter Control network. There are 16 Critter Control locations across Pennsylvania that remove bats, squirrels, raccoons, mice and other small animals.

“Usually August is a little bit of a mixed bag with all kinds of animals, but majority of the work we have going on right now is for bats,” Fichter said.

Bats are beneficial because they eat insects. However, they can become pests when they roost indoors instead of nesting in caves or tree cavities, according to Critter Control.

Bats help to cut down on mosquitoes, which spread diseases, including disease West Nile virus.

But once inside a home or business they make rustling noises at night and can spread their own diseases.

“A lot of people don’t even realize they have bats,” Fichter said. “One of the main ways people realize it is they go up into the attic, they get decorations down for the holidays or something like that, and then they see the bat guano up in the attic.”

Guano is the accumulated bat waste. Homeowners often find the waste in attics or droppings near entry points, which are sometimes mistaken for mouse droppings, he said.

Bats in Pittsburgh can carry rabies and damage buildings with their droppings.

Bat feces may contain bacteria that causes histoplasmosis, an infection caused by breathing in fungal spores that can be harmful to humans and pets.

The health department said that as long as no direct human contact with the bat has occurred, it can be released outdoors.

However, if someone has a known bite or scratch from a bat, had made direct contact with a bat when a bite or scratch cannot be ruled out or finds a bat in a room with a sleeping person, an unattended child, someone with cognitive impairment or an intoxicated person, post-exposure prophylaxis (PEP) an emergency medical treatment may be necessary to prevent rabies after a potential exposure. Among the 21 people exposed to bats in 2024, two were prescribed antibiotics, seven received a tetanus vaccine, 18 started rabies PEP, and 10 completed the PEP, according to health department data.

The health department receives animal bite reports online and by phone. The reports are investigated to determine if there was a possible rabies exposure to the person involved.

Bite reports come from health care providers after a person seeks care for an animal bite and from concerned residents after encountering a wild animal or finding a bat in their residence.

The Pennsylvania Department of Agriculture has regulatory authority over the management of exposed animals and the county’s Public Health Laboratory tests deceased animals for rabies when there is a concern that the animal may have had rabies.