Bats on ASU campus provide valuable services, nothing to fear

ASU has a bat population, which nest in the roof of the Psychology North building of the Tempe campus. Every fall students and faculty count the bat population on campus.  (Photo by Murphy Bannerman) ASU has a bat population, which nest in the roof of the Psychology North building of the Tempe campus. Every fall students and faculty count the bat population on campus. (Photo by Murphy Bannerman)

Behind the concrete facades and gutters and wedged into expansion joints on several of buildings on the Tempe campus hang colonies of bats.

While most students will never notice them as they make their nightly flights, several ASU students and faculty members are devoting their time to preserving the decreasing population of bats that call ASU home.

ASU Arboretum Volunteer Program Coordinator Deborah Thirkhill, who also runs the ASU Bat Watch internship program, said many people are scared of bats, but those fears are unfounded.

"They are the cutest little furry things," Thirkhill said. "It's just the mystique around them. I think they look like little flying Chihuahuas."

In 2010, ASU workers and officials began noticing many bats roosting in the expansion joints at Sun Devil Stadium, especially during the 7 p.m. September football games, Thirkhill said.

"There were just thousands (of bats) coming out at game time," Thirkhill said.

The following summer, after all the bats had left for other roosts, officials caulked the expansion joints so the bats could not roost there the following fall when they returned, Thirkhill said.

Since then the bats have found buildings to roost in and Thirkhill and several student interns with ASU Bat Watch have been observing and studying the habits and patterns of the on-campus bat population.

"The bats are wildlife," Thirkhill said. "They belong to the public. They aren't pests or vermin."

Bats on Campus

While several types of bats have been spotted on campus, the most common type is the Mexican free-tailed bat, which remains small and mainly eats small flying bugs.

"I've heard several different variations of how many pounds of mosquitoes (bats) can take out," Thirkhill said. "It's a lot. It's a big volume of teeny weenie insects."

The bats' diet has become an essential part of ASU's pest prevention strategies, Thirkhill said.

"They'll take out all the bugs around a light, including mosquitoes and mosquitoes that carry West Nile," Thirkhill said. "It gets rid of them without spraying toxic chemicals."

The bats are only active on campus from approximately September to May at dusk when they leave their roosts to eat.

Thirkhill estimates there are approximately 400 bats that fly in and out of campus each night, a number which is different from how many roost on campus, because bats follow the bugs to campus but may not live there.

"You really can't get bats off campus, because they will roost around campus and come on campus anyway," Thirkhill said. "You will still get bats on campus. They are all over, not just at the stadiums."

The most common buildings where bats live are Psychology North and the Tempe Town Center, Thirkhill said. They used to be more common in the Schwada Building and Lot 2, but many of these roosts have been caulked up after complaints from students and faculty.

Thirkhill said the professors in these buildings all know about the bats but have not complained, which means the roosts can remain intact.

"The professors all know about them, and they kind of like them," Thirkhill said.

In recent years, there has been a decrease in the number of bats roosting and coming onto campus, which is what the Bat Watch program is seeking to investigate, Thirkhill said.

"With the stadium roost gone, maybe they are moving around, but it just seems like a decrease (in bats this year)," she said.

Bat Watch

ASU Bat Watch counts the bats on campus and studies their habits. The group also occasionally intervenes when bats need a new home because their old roosts are in danger of being destroyed.

Wildlife conservation senior Sarah Schimpp has been working with Bat Watch since she started at ASU as a freshman. Even though she only received credit for her work one semester, she has continued to remain involved, because she enjoys the programs and the nocturnal creatures.

Schimpp has participated in the bat counts, where she and other volunteers go with Thirkhill to known roost sites and look for signs of bats.

This can be challenging, but Schimpp said she has gotten used to counting them and noticing the differences between birds and bats.

"Unless you are looking for (bats), you aren't going to see them, " Schimpp said. "You have to look for them."

Bat Watch is also working on building a new roost to go in the Tower Center, which is perfect for the new roost, because it is separated from other more densely populated parts of campus and the structure lends itself well to the project.

The project has been especially hard, Schimpp said, because none of them have experience with design.

Bats in the area prefer well-insulated areas for their roosts, which has made designs difficult, because they require a different material than most bat boxes.

Schimpp said they found a special type of material made from concrete and styrofoam called EF Blocks that creates the insulation bats require and meet other requirements.

"We wanted to build something sustainable," Schimpp said.

Thirkhill and the students in Bat Watch hope to get the roost built and placed in the Tower Center soon, so they can be begin attracting bats to the roost with the smell of their guano and their high-pitched sounds.

Thirkhill said they had originally chosen several other spots to put the roost but decided to settle on the Tower Center after speaking with facilities management and professors in the area.

"I just wanted everyone to know," Thirkhill said. "Their opinion has been asked and no one has a problem with it."

Schimpp said she has enjoyed working with Bat Watch, and it has helped her decide what she wants to do after graduation because of her exposure to the bats.

"They can fly!" Schimpp said. "They are the only mammal that can fly. They are also furry and cute."

Vampire Bats

Most dislike for bats results from misconceptions and bad information people have on the creatures, genetics senior Karina Ramirez said.

Ramirez said even though people are scared of bats, they are a valuable resource for their area and they provide great services.

"We want people to know bats are really a good thing to have on campus," Ramirez said. "Most of them are insect-eating bats or pollinators. They are very important."

One reason Ramirez, who joined Bat Watch a year ago, decided to volunteer with the program was her interest in the misunderstandings about bats.

"(I was interested in) how misunderstood bats are," Ramirez said. "A lot of people think they are scary, gross and dirty, but it's not true at all. Most of the things people think about bats are just not true. They're myths."

Ramirez said she has heard that people are scared of bats because they think that they will fly into their hair or directly at them, which is not true.

"They don't like be close to humans," she said.

Thirkhill said having bats fly into someone is an irrational fear, because their echolocation is so perfect.

"They are such pro fliers with their echolocation," she said. "They never run in to anyone."

Another misconception about bats may stem from horror movies, but Thirkhill said she has been on calls about bats trapped inside buildings where people would hold their necks in fear they were going to be bitten. This is not true.

"This teeny bat is this big and we caught it," she said. "They all expected us to have to wrestle it when we caught it. It's such an anticlimactic event."

Another concern people have with bats is rabies, which some do carry, Thirkhill said.

However, bats don't attack people and Thirkhill advised that if bats are seen on the ground or hanging low in trees during the day, someone call facilities management, because that behavior is not typical of bats and denotes a sick animal.

With the new bat roosts soon to be placed and the efforts of Bat Watch, Thirkhill said she hopes the bat population is able to recover from the recent decline.

The bats, which have been at ASU for many years, are nothing to be concerned about, she said.

"They won't come back and suck our blood," Thirkhill said. "They are eating insects. They just want to be away from us."


Reach the reporter at or follow her on Twitter @shelbygslade

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