Saturday, June 20, 2009

Adirondack Bat Survey

What is your favorite bird/animal/flower? This is a question I am often asked, and for me it is a difficult one to answer because there are too many fascinating things out there to select just one favorite. That said, I am especially fond of bats. They are highly misunderstood animals that are actually linchpins in many ecosystems. If more people understood their importance, they might be as popular as baby seals and elephants. Sadly, it often takes tragedy to bring around a change in feelings, and for our bats, that tragedy is White-nose Syndrome (WNS).

For those who still haven’t heard, WNS appeared suddenly in a handful of caves in the Albany region 2-3 years ago, and it has since spread like wildfire, infecting winter colonies in New York, Vermont, and New Hampshire; a couple cases turned up last year in Pennsylvania and West Virginia, and most recently in Ontario and Quebec. The result has been upwards of 100% mortality in the caves. That’s thousands, if not millions, of dead bats. Little brown bats (Myotis lucifugus) seem to be the hardest hit, which could turn a very common species of bat into an endangered species almost overnight. A new, cold-loving fungus (a Geomyces) has been identified in the caves and on the bats. Infected bats appear to be starving to death, but no one knows if the fungus is the cause or merely a symptom. The bottom line, however, is that bats are dying at an unprecedented rate, and species survival may be hanging in the balance.

To help better assess the situation, the NYS Department of Environmental Conservation (DEC) has solicited volunteers around New York State to help conduct audio bat surveys this month. I eagerly threw my hat in the ring and Wednesday night we did our first survey.

Because bats are nocturnal, they can be difficult to locate and count. One technique used by researchers is mist-netting, wherein bats are snagged in fine nets stretched across streams or cave entrances. Tangled bats are carefully removed, identified, sexed and even tagged before release. Another technique uses bat detectors, devices that pick up the echolocation calls of bats (used to navigate and to find prey) and alter them so the human ear can hear them. Like bird songs, bat calls are species specific in pattern and frequency (as in kilohertz).

For these surveys, the DEC shipped out large bat detectors that anchor to the roof of a car with a massive magnet. The detector is then plugged into a computer, which runs a program that records the calls. Surveyors also hook up a GPS tracking device, which determines where they are and where each recorded bat call was recorded. Once the equipment is up and running, the survey team drives a designated route at about 18mph after night has fallen.

I didn’t have high hopes for locating bats, and during the first 20 minutes or so, all the detector picked up was random static. Then, all of a sudden, there it was: the very distinctive popping chirp of a bat! I was ecstatic! We were out for the better part of two hours, and as the night darkened, we started to pick up more and more calls. The majority were concentrated around the street lights, which came as no surprise since insects are attracted to the lights and make for excellent hunting.

I haven’t memorized the different calls of each species of bat, but I suspect we had at least two, possibly three. New York is home to nine species of bats, including the Federally endangered Indiana bat (Myotis sodalis). Fortunately not all species overwinter in caves; three are migratory and fly south in the fall. One, the Hoary Bat (Lasiurus cinereus), is a species the DEC is interested in tracking, and it is possible we were picking up some of these.

Every evening when I walk the dog, I keep my eyes open for bats. In the past, I usually saw a few as they flitted across my yard or the overlook, silhouetted against the fading night sky. For the last two years, I haven’t seen a single bat, and this, combined with the increased number of mosquitoes, to me suggested that local bat populations were almost non-existent and it saddened my heart. The data we collected Wednesday night was reassuring: not all the bats are gone. Hopefully we will find a cure to WNS before it is too late.

Related Stories

Ellen Rathbone is by her own admission a "certified nature nut." She began contributing to the Adirondack Almanack while living in Newcomb, when she was an environmental educator for the Adirondack Park Agency's Visitor Interpretive Centers for nearly ten years.

Ellen graduated from SUNY ESF in 1988 with a BS in forestry and biology and has worked as a naturalist in New York, New Jersey, and Vermont.

In 2010 her work took her to Michigan, where she currently resides and serves as Education Director of the Dahlem Conservancy just outside Jackson, Michigan.

She also writes her own blog about her Michigan adventures.

3 Responses

  1. Mary Thill says:

Wait, before you go,

sign up for news updates from the Adirondack Almanack!