Biologist Craig S. Hood holds a Mexican free-tailed bat _ the species that is roosting in various spots around Texas A&M's campus this season after being ousted from Kyle Field.
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An estimated 250,000 or so Mexican free-tailed bats that typically live in Kyle Field had already migrated south of the Texas border by the time the west side of the stadium was reduced to rubble.
When the time came to return to their home in Aggieland at the start of spring, half of it was gone, and entrance points to the other half were blocked with nets as an effort by Texas A&M University to keep them out. With not many options, the bats have started taking up residence around campus, and even caused a temporary shutdown last week of the natatorium in the school's Rec Center, which is also under construction.
Bat experts warned human-bat contact would increase during the renovation without an effort to accommodate them, but advocates say there's still an opportunity to control, or even embrace, A&M's bat population.
Dianne Odegard, education and public outreach manager for Austin-based Bat Conservation International, said bats hanging out across the street from Kyle Field were to be expected, because there's a cavern-like atmosphere underground near the pool.
"It is not at all surprising, and was predictable," Odegard said. "Unmitigated eviction of a large colony of bats from a long-term roost will always result in suddenly-homeless bats, and the problems inherent in that situation, for bats and for people."
The handful of small bat houses at the golf course, polo field, west campus, Riverside campus and the Texas A&M Farm is a start, but Odegard said the presence of bats on campus likely will continue for the foreseeable future unless larger bat houses are installed quickly.
Odegard suggested a "community-style 10x10x10-foot bat house with the ability to host 30,000 bats would be ideal" for A&M.
The situation has unfolded on other college campuses, including the University of Florida, which has a pair of bat houses with a 750,000 bat-capacity to contain its 300,000 Brazilian free-tailed bat population. Those bats do not migrate like A&M's Mexican free-tailed bats.
According to Mark Hostetler, professor of wildlife and ecology at the University of Florida, the school's behemoth bat houses were built to transplant the bat population inside of James G. Pressley Stadium, the home of Percy Beard Track, to elsewhere on campus. It took the bats a few years to warm up to their new home, but the bats no longer are a nuisance and have become a national draw.
"It's now one of the major wildlife attractions on campus," Hostetler said.
Odegard said it's not too late for A&M to take control of the bat population with large bat houses, but there will be some health risks for bats.
"Eviction of a colony this size causes fragmentation of the colony, which always results in some mortality," Odegard said. "Bats often swarm at, and roost for a time on the outside of buildings they once occupied, making them vulnerable to avian predation, and in the case of a large university like A&M, with many buildings available to the bats, they will also be vulnerable to whatever actions the maintenance staff is instructed to take to remove them from the buildings they subsequently will occupy."
Christina Robertson, director of environmental health and safety for Texas A&M, said to not touch a live or dead bat on campus, and to call A&M's SSC facilities services if one is spotted.
Odegard said bats will remain in the area and keep bothersome insects in check when the Aggies kick off the 2015 home season in the newly renovated Kyle Field on Sept. 12 against Ball State. Students can feel safe with their campus co-habitants, she said.
"The common-sense recommendation of simply never attempting to handle a bat will protect people from the possibility of a bite from a frightened bat," Odegard said. "Like any wild animal, a bat that feels threatened may bite, though bats in general, and especially Mexican free-tailed bats, are not aggressive."
Experts work to make Kyle Field bat-free after renovation
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The 12th Man has had to share its Kyle Field home with an estimated 250,000 bats in recent years, but a Texas A&M University official and bat experts say it is unlikely fans will see much of the winged residents in the stadium by the time the $485 million renovation project is complete.
The combination of thorough exclusion efforts made by Texas A&M to rid the 87-year-old stadium of Mexican free-tailed bats and the timing of the west side implosion will force a majority the state's official flying mammal to roost elsewhere when they return to their renovated home from wintering in Mexico. The push to rid the stadium of bats could save the university thousands of dollars every year by not having to clean their droppings, but could increase human-bat contact in the area for a short time, one of the very things the exclusion effort was intended to reduce.
According to Texas A&M Chief Business Development Officer Phillip Ray, Manhattan-Vaughn Construction implemented electronic sonar systems to deter bats from entering the stadium in fall of 2013 and hung netting in ideal roosting locations. He also said colonies of bats were removed by trained experts when discovered.
Whatever bats remained in the stadium this fall made their exit with a "scare charge" that preceded the west stadium collapse, Ray said in a message.
"Manhattan-Vaughn and their bat mitigation experts had conducted several inspections in the weeks and days leading up to the implosion to locate and remove any colonies that might be residing in the west stands," he said. "The final inspection, conducted in the days leading up to the implosion, found no bat colonies remained in the building."
Ray also said netting and extraction will continue once the renovation is complete to prevent any colonies from returning.
Dianne Odegard, education and public outreach manager at Austin-based Bat Conservation International, said these efforts pose short-term problems for the 250,000 displaced bats and humans in the area.
BCI has consulted Texas A&M officials intermittently since 2003 on bat issues and advised the school in 2013 to take the steps it has now implemented to prevent roosting.
She said it's very likely human-bat contact will increase as a result of bat exclusion from Kyle Field.
"Bats that are suddenly homeless can be confused and are more vulnerable to predators and may keep trying to come back even if they can't get in any longer," Odegard said. "Those bats that didn't find new roosts after being excluded from Kyle Field may come back in spring and try to find their old roost in the stadium."
The bat houses on A&M's campus at the golf course, polo field, west campus, Riverside campus and the Texas A&M Farm can help minimize the number of bats searching for an alternative home in the area that could lead to increased human-bat contact.
"When people do exclusions without careful planning and the use of artificial roosts is human-bat contact -- the very thing exclusion is meant to prevent -- is much more likely to happen," Odegard said.
Even with the bat houses installed on campus prior to the implosion, Mexican free-tailed bats have very particular roosting needs that the houses may not meet, according to A&M wildlife and Fisheries professor Michael Morrison. He said the amount of light that enters the house and presence of predators are very important factors in bats choosing a roost site.
Morrison said this particular breed of bats prefer cool, dark areas to roost in to escape the intense summer heat. Bats have lived in the area long before the existence of Kyle Field and are able to find a suitable home in a cliff side, a hole in a tree, a cave, one of Texas A&M's buildings or one of the thousands of artificial structures surrounding campus in Bryan-College Station.
"If they can find similar structures they won't return," he said. "It's going to be a wait-and-see sort of thing."
While bats roam the area upon return in the spring for a new home, artificial or natural, the dispelled mammals pose a risk of rabies if they come in contact with humans during their search.
Odegard said the threat is small, but serious.
"When you get bitten by a bat you usually feel the bite, but it may not bleed or leave an obvious mark," she said. "Mexican free-tailed bats are generally non-aggressive and don't always bite when they feel threatened."
Bats have been and will continue to be vital to rural ecosystems like Bryan-College Station as they consume thousands of pounds of insects that can destroy crops, but keeping them in check so they are not a nuisance or a health concern on campus and in the area will be an ongoing challenge, Odegard said.
"It's a balancing act protecting humans and wildlife," she said.