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John Reitman

By John Reitman

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Endangered bats thrive on 90-year-old Florida course

 

Scientists aren't sure why Florida bonneted bats have returned to Granada Golf Course (above) in Coral Gables, Florida, or if they've gone previously undetected there.
With a body just 3 inches in length, but a wingspan of nearly 2 feet, the Florida bonneted bat should be easy to spot. Problem is, there are so few of them remaining in the wild that finding one is a challenge. Except at Granada Golf Course in Coral Gables, Florida.
 
The role of golf courses as habitat for wildlife is well documented. According to Audubon International, there are 835 properties in the cooperative sanctuary golf course program. Fox, elk, deer, coyote, mountain lions and even bears are regular visitors on golf courses all around North America as are all manner of birds of prey and other rare species. It's not often that a golf course is singled out as habitat for bats.
 
When the sun goes down, an unknown number Florida bonneted bats, so named because of their large, broad ears, emerge to hunt insects in the skies above the nine-hole, Donald Ross design built in 1923 five miles from downtown Miami.
 
Just how many Florida bonneted bats are living in the wild or even around the golf course is anyone's guess. Researchers estimate the number of Florida bonneted bats across all of South Florida to be somewhere between 300-1,000. The number of bonneted bats roaming the skies around Granada also is unknown and could be anywhere between a half-dozen and 50, researchers say. The bats are protected under the federal Endangered Species Act, and until researchers are able to physically find their roosting sites, any guess on how many there are is just that - a guess.
 
"We really do not have a good estimate because we have not found any roost sites," said Kisi Bohn, Ph.D., research assistant professor at Florida International University in Miami. "My guess is about 500, but again it is very hard to estimate until we find more roosts and do more widespread acoustic surveys."
 
Researchers use ultrasonic recording equipment to detect the bats and their unique high-pitched call. Even with such state-of-the-art technology it can be difficult to trace the bats' activity, because the Florida bonneted bat flies higher and much faster than most other bat species.
 
"You record one, then you record another one 10 minutes later," said Frank Ridgley, Ph.D., conservation director with Zoo Miami. "But because they are so mobile, have you recorded the same bat twice? You don't know.
 
"So, how many are at the golf course? We can see four or five at a time, but does this mean there are 30 or 40, or just six?"
 
Found only in Miami-Dade, Collier, Lee and Charlotte counties in South Florida, the bats are a tropical species that Ridgley says were first observed in Florida in the mid-1930s, about the same time fossils records were found indicating they thrived in the area since prehistory. That said, they have not been found in Monroe County in the extreme southwestern corner of the state.
 
And why not?
 
"No one knows," Ridgley said. 
 
"The problem is we just don't know enough about them."
 
Other than its large wingspan and voracious appetite, little is known about the Florida bonneted bat. In fact, so little is known that scientists can't even agree on how many reproductive cycles the animal goes through per year. They do know, however, that each cycle includes just one offspring and they rarely are found roosting in the wild. Instead, they almost exclusively are found nesting only in boxes, in people's homes and other manmade structures.
 
So far, the location of the Granada colony's roost is a mystery.
 
Colonies in Charlotte and Lee counties have been detected using ultrasonic equipment within as little as 15 minutes after dusk. The Granada colony's calls have been picked up within just a few minutes of dusk, leading Cyndi Marks, founder of the Florida Bat Conservancy to one conclusion.
 
"We think they live close by (the golf course)," she said. "The old barrel tile roof is a perfect roosting location, and there are a lot of old homes around the course. They also like cavities in palm trees."
 
Researchers believe that urbanization has contributed to the bat's declining numbers. In fact, only four reliable colonies are known throughout the state: two near Punta Gorda in Southwest Florida, the one at Granada and another near the zoo, Ridgley said.
 
Likewise, scientists don't know why a colony appears to be thriving near the golf course. The bats typically are drawn to open areas like golf courses, and researchers haven't ruled out that Granada coincidentally is to be one of the few places in Miami-Dade County that has gone relatively undisturbed during the past 90 years. 
 
"Bats, in general, love golf courses," Marks said. "They have long flyways and are perfect places to forage."
 
However, most bats also are drawn to golf courses because they have ponds or lakes where they can find a drink at the beginning of each nightly foraging period. Granada has no pond, confounding scientists even more.
 
"When I first heard about them being on a golf course, I thought it was going to be a big golf course with landscaping and water features," Ridgley said. "But there is no water anywhere. 
 
"Nothing about this place says this should be a hot spot for bats. There are people walking with their dogs all around it, and here is this critically endangered bat right in the middle of it. We don't know if they've always been here and have adapted to survive, or if something recently attracted them here."
 
There have been unconfirmed sightings nearby at The Biltmore resort and golf course, says Marks. But attempts to locate bats at another nearby course in Miami Springs have been fruitless.
 
FIU's Bohn believes the Granada colony has thrived at the golf course for as long as a half-century, and says the question isn't why this colony appears to be succeeding.
 
"I'm not sure why the Coral Gables golf course is such a hotspot," Bohn said. 
 
"I think a better question is why we don't see them on other golf courses and parks. That's exactly what we're trying to find out."
 
The bonneted bat is a high-flying animal, soaring hundreds of feet above the ground, which is a much different behavioral pattern than that exhibited by other bat species that race around the tops of the tree lines. 
 
The Florida bonneted bat is in the same family as free-tailed bats which have been observed in Texas flying as high as 5,000 feet above the ground and feeding on migrating moths at altitudes of 3,000 feet, Marks said. Although the bonneted bat doesn't have to fly that high to feed, its flying habits historically have made catching and studying them almost impossible. The bats at Granada, however, have reportedly been flying at altitudes more consistent with those of other bats. 
 
"On Florida's West Coast, they live in a more isolated area," said Zoo Miami's Ridgley. "In Coral Gables, it could have adapted to a different food source. It appears that they are flying lower there. They might have adapted to a whole new feeding behavior just trying to hang on. We just don't know yet."
 
Scientists don't know if that modified behavior means the bats have adapted to local conditions or prey. They have to find roosting locations and bat scat, known as guano, so they can analyze where they live and what they eat. Dogs specially trained at Auburn University to detect the guano of Florida bonneted bats have turned up nothing. 
 
"Their flight patterns are determined by where the insects are," Marks said.
 
Researchers also hope that raising public awareness might help them learn more about the bats.
 
"We're glad to see that they are getting some attention. People don't even know they are out there," Ridgley said. "We have to find where they live. This could be a small colony living under the tiles of someone's roof. A roofer making repairs could unknowingly wipe out a whole colony. It really is that simple."
 

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