Yesterday I visited an old graphite mine in Hague that once harbored the largest population of wintering bats in the state. Back in 2000, state scientists estimated that the old mine contained 185,000 bats. Last winter, they found only a few thousand.
Such are the devastating effects of white-nose syndrome [pdf], first discovered in upstate New York in 2006. Since then, the disease has killed 90 percent of the state’s bats and spread to hibernacula throughout the Northeast and as far south as Virginia.
Scientists from the state Department of Environmental Conservation returned to the mine in Hague yesterday to see if the decline is continuing. I accompanied them along with Carl Heilman II, who took photos for a story that will appear in the Adirondack Explorer.
Despite frigid temperatures outside, the mine remains above freezing all winter—ideal for sleeping bats.
The mine is a fascinating place, with a maze of corridors that lead to chambers, some with pools of water. In places, old timbers prop up the ceilings. We saw other reminders of the mine’s past: old shovels and buckets, rusting cables, iron rails.
When we came to one underground pool, wildlife scientist Carl Herzog pointed out hundreds of raccoon tracks in the wet soil. The patterns resembled abstract art.
“Do they come here for the water?” I asked.
“They come here for the bats,” Herzog replied.
Before white-nose struck, the ceilings used to be covered with bats. That’s far from true these days. As we walked through the mine, we scanned the roof with our headlamps to find a specimen here and there, or sometimes a cluster of two or three bats.
After leaving one chamber, biologist Scott Crocoll, remarked, “We’re lucky if there were fifty to sixty bats in there, and there used to be thousands.”
In the old days, little browns accounted for about 98 percent of the bats in the mine. At their peak, the mine probably contained around 200,000 little browns. Last year, DEC counted only 2,049. From what he saw yesterday, Herzog believes the little browns are continuing to decline.
“We definitely saw fewer of them than we did than last year in the same spots,” Herzog said.
Based on his preliminary assessment, Herzog believes the number of small-footed bats has not changed. He can’t explain why this species is faring better. One theory is that small-footed bats are a cold-hardy species that can better withstand the side effects of the disease.
The scientists also found one Indiana bat, which is on the federal list of endangered species. That’s an improvement from last year, when they found none.
“It’s hard to get excited about one,” Herzog said, “but it’s better than nothing.”
Photo by Phil Brown: Carl Heilman II at the mine entrance.