April 2009, Volume 7, Issue 4

Bats in the News

Finding Pride in East Texas Bats

East Texans should be very proud of their bats, reports the Beaumont Enterprise. The colony of 100 or so bats at the Trinity River National Wildlife Refuge is tiny compared to the 1.5 million Mexican free-tail bats that draw thousands of visitors to a bridge roost in downtown Austin, Texas, the newspaper conceded. But “these bats are special.”

The Rafinesque’s big-eared bats at the refuge 50 miles east of Houston are, the Enterprise said, “the rock stars of bats.”
“They’re the cutest bats we have in Texas,” Mylea Bayless of Bat Conservation International told the newspaper. But they’re “also a threatened species whose habitat has been dwindling steadily in the past century,” reporter Sarah Moore wrote.
Bayless is coordinator of BCI’s Southeastern Rare Bats Program, which includes the Rafinesque’s big-eared bats, as threatened in Texas, among its subjects. The species is found throughout the southeastern United States.
“They’re difficult to study because they don’t roost in large colonies,” Bayless told the Enterprise.” A colony of Rafinesque’s big-eared bats typically includes just 10 to 100 bats.
The Trinity River colony was discovered in 2004, when a refuge officer checked a long-abandoned house on the refuge land and found bats inside, Moore reported. The house had been slated for demolition, but the bats’ presence changed things. The new problem became how to keep the house from collapsing.
BCI helped out with a $10,000 grant to build two artificial bat roosts: cinder block towers that mimic the big hollow trees the bats generally prefer, the newspaper said. The bat towers now stand in a clearing near the house and the house is still there.
Refuge Wildlife Biologist Laurie Lomas, who has studied the colony for several years, said the bats typically move around among the towers and various rooms in the house. She said she recently found only one in the building and a total of 80 in the two towers.
The most distinctive feature of these bats is their large ears, which are adapted to detect the quiet movements of the moths, which damage trees and crops, that are their principal prey.
Bayless told the Enterprise that the relationship between the bats and moths is akin to that between police and speeding motorists. Just as police use radar to detect speeders and speeders buy devices to detect radars, moths evolved to become increasingly silent while bats increased their echolocation abilities – the high-frequency biological sonar they use to avoid collisions and pursue insects in the dark.
In the never-ending struggle between the bats and insects, Bayless said Rafinesque’s big-eared bats have become very quiet when compared to other bats. “People call them whispering bats.”
The big-eared bats live in bottomland hardwood forest, mostly roosting in hollowed-out black gum, bald cypress and tupelo trees, Moore reported. As their habitat of swamps and wetlands are encroached upon by humans, they often turn to abandoned houses and barns as sanctuaries, Moore wrote. And habitat, once protected by its inaccessibility, continues to shrink.
In the past, bottomland forests – characterized by swamps and wetlands – have been protected by their inaccessibility. However, encroaching civilization and prolonged dry conditions that have dried up the wetlands have resulted in increasing development in the habitat.
The price of losing this habitat and the bats and other wildlife that need it is not clear, but bats play a critical role in maintaining healthy ecosystems. “We don’t know what the implications are and that’s what’s so scary,” Bayless told the Enterprise. “You don’t know until you’ve lost them – then it’s too late to go back.”
Conservation efforts by the Wildlife Refuge, BCI and many others are designed to prevent that time of reckoning.

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