Friday, October 23, 2009

Catastrophic Decline of Bats

Last Tuesday Scott Darling, wildlife biologist with VT Fish and Wildlife, gave a lecture to our local Southeastern Vermont Audubon Society on the catastrophic collapse of bat populations in New England and NY due to White Nose Syndrome, which appears to be a highly infectious fungal disease.

Bats affected by the disease are unable to put enough weight on to carry them through 7 months of hibernation and end up dying of starvation. Bats have been leaving the cave, or hibernaculum, in the middle of winter in search of food and perish in their quest. Bat population in most caves have dropped by 90% or more, for example numbering in the tens of thousands in the Mt Aeolus cave in 2007 and now down to single digits. This will have a significant impact on our environment since bats are one of the major agents in controlling insect populations, particularly mosquitoes. Here is a map illustrating the spread of the disease:

There is no as yet known remedy against this disease and further spread across the entire country seems inevitable. Since bats are slow to reproduce, bearing only one pub a year, re-building the bat population, if a cure is found, will take many decades.

When I first moved into a log house in VT in the 80's I had bats in the attic. Once when sitting under a lamp reading I saw a shadow fly across the ceiling and discovered that a bat had found its way down. I saw on the wall near the ceiling in my bedroom. Before I could come up with plan however the bat had found its way back into the attic through some gap between the wall and the ceiling. That was the only time it ever happened.

I used to enjoy watching bats fly flutter about against a moonlit summer sky. Last summer I saw only two bats and none this summer. I did however see one of those doomed bats flying in broad daylight this past February near the CT River on the NH side. On April 16 of this year I saw a Little Brown Bat flying back and forth over a small pond catching insects for good 20 minutes, long enough for me to get some photos.

Here are a couple of very useful links:

The Nature Conservancy Bat Diaries and more on White Nose Syndrome


  1. Really nice pix of that bat, Hilke.

    I'm very fond of them as long as they're not in my house, but like you, I haven't seen a single one this year. Three years ago, the air around my house was full of them at dusk, last year a few showed up finally in late summer. This year, nothing.

    No idea whether it's the lack of bats or just the wet weather, but I've had dozens of mosquito bites this summer, too, where the most I've had in my breezy location in the past is two or three.

    What's happened to those little guys is just heart-breaking.

    Thanks for the pix!

    Jane (Shoreham)

  2. Thanks, Jane. There is some speculation that the white nose syndrome was initially introduced from Europe by cave spelunkers. It seems every day we hear or read of something else disappearing due to human activity.


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