On lookout for bats
A hibernating little brown bat with white nose syndrome.
Folks looking for where bats might come out, at a recent training in Grafton County.
I’m pulling mosquito netting over my head to step into the woods at dusk and stand still in front of an old barn. Hopefully I won’t get too many bites. More importantly, maybe I’ll see some bats pass by — little grey flurries headed out to catch their night’s meal of mosquitoes. The spring peepers are still singing this early June evening. The gray tree frogs have joined the chorus and the air is vibrating with the deep-throated hum of the bullfrogs. I have three other batty friends braving the mosquito-filled dusk with me. We’re standing strategically at each corner of the barn to record the total number of bats we see as they exit through the open eaves and a broken window. Later, we’ll submit the data to N.H. Fish and Game, to learn more about summer bat colonies in New Hampshire as part of a nationwide effort. This part of the research, counting bats, is something that anyone can do and it’s a terrific help to the scientists. To learn how, see information at the end of the article.
Researchers are concerned about bat populations because, unfortunately, most of the eight species of bats in New Hampshire are in trouble. Two of these species, the little brown bat and the big brown bat, use barns and attics to roost in summer colonies. Their populations have been decimated by a fungus,Geomyces desctructans, that causes white nose syndrome. It affects them during winter in the caves and mines where they hibernate.
The bats spend their summers in New Hampshire and throughout New England in warm barns and attics. This is where they have their pups. They feed in nearby fields, over wetlands and streams and along forest roads and edges. One bat can eat up to half its weight in insects each night!
In the fall, they gather up in swarms to mate and then go off to the caves to hibernate. Their bodies have enough fat stored for about five months of deep hibernation during which time their body temperatures drop and their metabolisms slow. The caves, with consistent temperatures between 40 and 50 degrees and high humidity at 80 to 100 percent, are ideal for hibernation. They’ve proven to be ideal for the fungus as well. The fungus grows on the bats’ noses and in the skin of their wings. It causes the them to awaken during hibernation, likely affects water and air exchange through their wings, and forces them to use precious energy at the wrong time. The bats die of starvation. Up to 90 percent of the little brown bat population in New Hampshire have disappeared since WNS was first discovered in 2007.
The fungus is new to science, but it has existed in Europe for a very long time. We do not know why it doesn’t seem to affect bats in Europe . It was likely transported to the U.S. by cave explorers. As the bats come out of hibernation each spring and go to their roosting spots, they,too, then carry and spread the spores. Most recently, it was found as far northeast as Prince Edward Island.
On our bat counting expedition, we are hoping that there are quite a few bats in this colony tonight and that they stay through the summer to have their pups. Little brown bats live a very long time, on average 20 to 25 years. They have only one pup per season, and so it could take decades for the population to recover.
The data we gather will be analyzed by N.H. Fish and Game and shared nationally with researchers working to understand and hopefully counteract the impacts of WNS.
Anyone can participate in this effort. All you need is about an hour at dusk, a couple of friends and some patience.
The data sheets and instructions are online at www.wildlife.state.nh.us/Wildlife/Nongame/bats/bat_count.html. For more information, write to firstname.lastname@example.org, with Bat Colony Count in the subject heading.
Cynthia Nichols is Peterborough Conservation Commission Alternate who volunteers to help coordinate the Summer Bat Colony Count in partnership with N.H. Fish and Game, N.H. Audubon and The Harris Center for Conservation Education in Hancock. Nichols can be reach at email@example.com.