Good news for bats

Little brown bats were once the most widespread .bat species in New York State, but its population has declined about 90 percent since the discovery of white-nose syndrome in a cave south of Albany several years ago.

Little brown bats in hibernation.
Little brown bats in hibernation. Photo by Larry Master.

Now there may be a bit of good news: the latest survey of caves in the Albany region detected an increase .in the number of little browns.

“While we remain cautiously optimistic of encouraging trends for some species seen more recently, it will likely take several years before we fully know how to interpret this,” said Kathleen Moser, assistant commissioner of natural resources for the state Department of Environmental Conservation.

DEC’s full news release follows.


The results of the winter survey of hibernating bats in New York are now available, the New York State Department of Environmental Conservation (DEC) announced today.  This survey was a cooperative effort among state wildlife officials, the U.S. Fish and Wildlife Service and numerous volunteers to monitor the effects of white-nose disease, a fungal infection that has devastated regional bat populations since it was first documented in New York in 2006.

The most encouraging observations came from surveys of the five hibernation caves in the greater Albany area where the disease was first discovered. Previous reports have suggested that little brown bat counts at these sites seem to be stabilizing in recent years. This year’s surveys saw substantial increases in little brown bats at three out of five of these caves. The largest and best documented of these sites saw an increase from 1,496 little brown bats in 2011 to 2,402 this year.  It is premature to conclude that population recovery is underway for this species, however, because of the small number of hibernation sites that have experienced increases and the fact that alternate explanations are plausible.  Bats are highly social animals and observed increases could be the result of consolidation of individuals from other hibernation sites, for example.

“While we remain cautiously optimistic of encouraging trends for some species seen more recently, it will likely take several years before we fully know how to interpret this,” said Kathleen Moser, DEC’s Assistant Commissioner of Natural Resources.  “DEC is assisting in national bat research and with those seeking solutions to the effects of the white nose disease.  As a preventative measure we can take now, we encourage the public who enter caves recreationally, to refrain from entering hibernation sites while bats are there.”

Based on this year’s survey, total observed declines in population attributed to the disease for tri-colored bats have been revised upward.  Prior to the arrival of white-nose disease in 2007, a total of 2,285 tri-colored bats were counted at 37 representative hibernation sites in the state.  Since that time, a total of 112 bats were observed during surveys of those same sites, suggesting a statewide decline of 95 percent for the species. Northern long-eared bats have also been affected with a 98 percent observed decline (18 individuals observed in 36 sites compared to a pre-disease total of 911 bats at the same sites).  Although neither bat was considered a threatened species prior to the arrival of white-nose disease, both species are now extremely rare in New York.

No surveys were performed this year for the federal and state endangered Indiana bat. Previous surveys indicate that losses for this species have totaled 71 percent statewide (15,650 individuals remaining, down from a high of 54,689).  The population status of Indiana bats in New York will be reassessed in 2013.

Records of small-footed bats, a rare species even prior to the disease, show only a relatively small decline of 13 percent.  This species is difficult to count due to its secretive habits when hibernating, but focused survey efforts this season have bolstered previous observations that the impact of the disease is far less severe for small-footed’s than for most other hibernating bats.

Prior to the arrival of white-nose disease, the little brown bat was the most common bat species in New York State and has been observed hibernating in more than 100 caves and mines here.  Statewide losses for the species attributed to white-nose disease remain at approximately 90 percent. For more information on white nose syndrome in New York, visit the DEC website at


About Phil Brown

Phil Brown edited the Adirondack Explorer from 1999 until his retirement in 2018. He continues to explore the park and to write for the publication and website.

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