Trouble in the bat cave

Chances are you have heard about the sudden, massive die-offs that are threatening bat colonies across New England and the Northeast. But if you haven’t — and even if you have — here are some pertinent facts gleaned from an interview earlier this week with Geoffrey Krukar, a wildlife technician with the state Department of Environmental Protection’s Wildlife Division.

"White-nose syndrome" is the name given to the epidemic, because many of the dead bats that have been found this winter have a ring of white fungus around their noses. The bats are being found dead in caves (known as hibernacula) where they hibernate.

Little is known yet about the malady. It’s unclear, for example, whether the fungus is the cause of death, a contributing factor, or merely a symptom of what is actually killing the bats. Scientists haven’t figured out where the pathogen is coming from, or how it is spreading.

As of now, white-nose syndrome has not been identified in Connecticut, although it has been found in New York, Massachusetts and Vermont. The nearest caves in which the syndrome has been identified are in Chester, Mass., and Kingston, N.Y. The largest mortality incidences have occurred around Albany. In one cave that held 15,000 hibernating bats last year, 1,500 were found alive this year.

By far the greatest proportion of deaths has been seen in the relatively widespread

little brown bat . Other species affected in our area include the northern long-eared , small-footed and Indiana bats , as well as the eastern pipistrelle . The only hibernating species in which white-nose syndrome has not been detected is the big brown bat . Migratory species that return to our region in summer, including the red, silver-haired and hoary bats , have not been affected.

Krukar is reluctant to estimate what the long-term impacts will be. He points out that bats are the most important predator of night-flying insects, but as to whether we will see a noticeable increase in moths, mosquitoes and other bugs — or an absence of bats — he won’t speculate. In New York, concern for the Indiana bat is high because of its already low numbers. It is on the federal endangered species list, and a significant percentage of the species’ population is in New York State.

Wildlife enthusiasts and spelunkers are being cautioned against entering caves where white-nose syndrome may be present. If they do so anyway, they are urged to take steps against spreading the disease. In Litchfield County there are six known bat hibernacula, including in Salisbury and Winsted, as well as in New Milford, Terryville, Morris and, the largest one, in Roxbury.

Meanwhile, wildlife experts and pathologists are racing to isolate the problem and identify its extent. Krukar and others are investigating sites whenever possible for signs of the syndrome. Where direct surveys would cause unnecessary stress to the animals, they are looking for indirect signs such as increased bat activity around cave entrances. Many affected bats are evidently emaciated and are leaving their hibernacula early in search of food.

Further details and updates are available at the U.S. Fish and Wildlife Service Northeast Region Web site, fws.gov/northeast.

Fred Baumgarten is a naturalist and writer. He may be reached at fredb58@sbcglobal.net. His blog is at thatbirdblog.blogspot.com.