It’s estimated that only about one-fourth of the Indiana bat population actually lives in Indiana, where the first specimen was identified in 1928. A sizable number of the tiny creatures, a federal endangered species since 1967, calls the Kingston area home.
Out of a U.S. population estimated at 500,000, Indiana bats number about 54,000 in New York state, the fourth largest population of the species nationwide. And according to Alan Hicks, a mammal specialist with the state Department of Environmental Conservation’s Endangered Species Unit, about 39,000 of New York’s Indiana bats live in Kingston and the surrounding communities.
In 1999, a 426-acre portion of the 700-acre Williams Lake resort property in Rosendale was preserved in a conservation easement, including 10 acres deeded to the state to protect an Indiana bat habitat. Three years earlier, the discovery of a hibernating Indiana bat in an abandoned limestone mine in Kingston briefly threatened to hold up the development of the Kingston Business Park off Delaware Avenue.
And while some view bats as a nuisance and a rabies threat, the critters play a key role in the region’s ecosystem, consuming vast quantities of night-flying insects, including mosquitoes and crop pests.
“The females will, when nursing their young, eat up to about half their weight in flying insects a night,” Hicks said.
Once numbering in the millions, the Indiana bat population declined to about 900,000 by the 1960s, with 80 percent wintering in a handful of caves and abandoned mines. The population reached a low of about 400,000 nationwide before rebounding.
Because the bats are so fragile, Hicks won’t say exactly they reside in Ulster County, except that the local population hibernates in three ungated mines close to one another. He also said the Department of Environmental Conservation plans to gate the mines in the future to protect the bats.
Indiana bats spend winters hibernating in caves or mines, often with more than 300 sharing a square foot of space, Hicks said. He said they hang for weeks on end without moving during hibernation and take several minutes to wake up enough to move after they’ve been disturbed.
“Thus, they are very vulnerable to all kinds of bad things,” Hicks said.
If the bats are disturbed too often during hibernation, he said, they will burn up their stored fat before the spring.
Indiana bats also are vulnerable to mine collapses and flooding, as well as predators like racoons and mice if they aren’t hibernating in an unreachable location or are knocked from their roosts.
One of nine species of bats found in New York state, Indiana bats are roughly 2 inches long, weigh an average of 6 to 7 grams, and have a life span of 10 to 15 years. They generally are dark gray to grayish-brown and often have a pinkish nose. Their feet are about a third of an inch long, with little if any hair.
Generally found in tightly packed clusters, the bats return to the same spot each winter to hibernate. The caves or mines where they hibernate average 37 to 43 degrees Fahrenheit.
Hicks said the Department of Environmental Conservation discovered New York’s population of Indiana bats during surveys of animal species. He said the agency tracks the bats by visiting their habitats in the winter, photographing them and placing transmitters on them.
If the state can demonstrate the species is increasing and its major habitats are protected, the Indiana bat can be removed from the endangered species list, Hicks said. He said the goal is to ensure the Indiana bat is common enough and protected enough to be taken off the list.
“We have an obligation to keep these things around,” he said.
According to the U.S. Fish & Wildlife Service, vandalism and indiscriminate killing have destroyed much of the Indiana bat population. And some early attempts to keep people out of hibernacula – where the bats hibernate – inadvertently made the caves unsuitable as a habitat. Specifically, improperly constructed gates altered the air flow, trapped debris and blocked entrances by not allowing enough flight space. Altering the air exchange by opening additional entrances also can change cave temperatures and humidity, rendering the cave unsuitable.
In an effort to reverse the decline of the Indiana bat population, vandalism and human disturbance in the winter habitats were addressed first, according to the Fish & Wildlife Service. But when the populations continued to decline, biologists examined places where the bats spend their summers. Loss and degradation of summer habitats and roost sites due to water impoundment, stream channeling, forest clearing, housing development and clear-cutting are seen as possible factors, but additional research is needed, according to the federal agency.
“We’re trying to address the questions of development pressure and how important is development pressure on the security of the population,” Hicks said.
Additionally, according to the National Wildlife Federation, wind-powered turbines could pose a threat to Indiana bats and other bat species, as well as birds. Some studies suggest the turbines might account for thousands of dead bats and birds yearly, the federation says.
While the Indiana bats hibernate through the winter, in the spring the females will leave hibernation before the males to give birth, Hicks said. He said the females leave during the first warm stretch of weather, around or after April 15. They then head to nursery areas and have their pups about a month later, with one pup per mother, Hicks said. He said it takes the pups about a month to learn to fly.
“The males are bums in many ways, and the females are the ones who are driving the population and really incurring all the risks,” Hicks said. He said the males often hibernate longer than the females, and their only function seems to be for reproduction in the fall.
Hicks said the female Indiana bats form maternity colonies in the spring under the loose bark of trees. The females choose trees that are kept warm by the sunlight so their young do not have to use any energy to stay warm, he said. The maternity colonies move from night to night.
The Kingston-area bat population is interesting, Hicks said, because it does not move very far. He said most of the bats the state has tracked from Kingston have turned up in Poughkeepsie or northern Orange County.
Hicks said the Kingston bats are very much homebodies because they only travel within approximately 40 miles of the areas where they hibernate. Bats studied in Pennsylvania, he said, travel about 60 miles.
The homebody nature of the region’s bats can be attributed to the fact that the population is newer to the area than others, Hicks said. He said Indiana bats have been in places like Missouri and Kentucky much longer and are more dispersed.
By Ariel Zangla, Freeman staff
22 July 2007
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