Thursday, August 18, 2011

The Results Are In

Last January, Mackenzie Hall, a Private Lands Biologist with the Conserve Wildlife Fund of NJ (CWF) gave a presentation on bats to the Burlington County Natural Science Club. Mackenzie's enthusiasm for these flying fur-balls was quite infectious.

It helped that I already had an interest in bats. And while I've seen and photographed bats I knew that they were in trouble. Sadly white nose syndrome is taking quite a toll. So when at the end of her talk Mackenzie mentioned a citizen science project consisting of bat surveys and that she was looking for volunteers I made sure to sign up.

Fast forward a few months and my friend Patty, aka Bat Girl, forwards an email asking if I want to do bat surveys. Patty does horseshoe crab and shorebird surveys for CWF and learned of the survey via a call for volunteers email. I don't know if we disappointed Mackenzie when she learned her two volunteers were just one team. She never said, but she made up for it by giving us two routes.

But first there was training. We met a a park in central Jersey and after a brief talk on the bats of NJ we were introduced to the gizmo. The gizmo is more formally known as an AnaBat detector. We learned how to turn on and off the gizmo, how to change the batteries (rechargeable), how to set the controls, and most importantly, to never never ever let it get wet. Apparently even the slightest fog will turn this $2000 + device into useless brick.

We then learned how to put the gizmo into a homemade wooden bracket and strap it to the top of a car. You see, the survey was done by strapping it on, powering up, and then driving at 15 MPH along the specified route.

As I mentioned, Bat Girl and I did two surveys. The first was near my home along the Delaware River. Along back roads through several towns ending in my hometown of Edgewater Park. Fortunately we didn't encounter much traffic.  The second route was clear across the state and ran through the Pine Barrens.  It was a route selected by Mackenzie by looking at Google maps. No one had ground truthed it. So Bat Girl and I took a Saturday and did a dry run. It took us four hours. The main part of the route was via sand roads in the Pine Barrens. Roads that don't see much traffic. Roads so tight with brush I had to fold in my mirrors and remove my radio antenna. Don't tell Mackenzie, but the gizmo took a beating from the branches. As did my car, all nice and scratched up now (but I bought it to drive these roads so the scratches were expected).  Our first try to drive through the Pines ended when the road went into a lake. We saw where it came out on the other side. But it was too deep. So we backtracked. Our second attempted also ended with a water hazard blocking our path. Not wanting a repeat of this we again backtracked.

The third time was a charm, although we needed to make a couple modifications to the route to avoid private property, places with big gates that would have blocked our path. But I was familiar with most of the area, from nightjar and frog surveys, as well as plant geek field trips. There were still plenty of tight spots and large puddles to maneuver around. And for most of the route 15 MPH would have been reckless.

Unlike other surveys I've done for frogs which you can hear or birds which you can see and hear, this survey has only static on the gizmo's speaker. If you're lucky the static is the ultrasonic sounds of the bat converted into human hearable frequency ranges. But you don't really know if your survey found any bats.

We did. Our first survey recorded 37 call sequences of two different species, big brown bat and hoary bat. Our second only 34 call sequences but three species, adding the eastern red bat. The full results for our survey runs can be found here (page one) and here (page two).

I don't know if finding 30+ instances of two or three species of bat is good or bad as I don't know the historical context. I do however think that it is pretty cool that these animals are living within two miles of my home. Also cool is that we did this in the year of the bat.

So the next evening you are outside at twilight look up. And maybe you'll see a bat or two. And be sure to thank them for eating for eating those pesky mosquitos.

1 comment:

Anonymous said...

One fine story! Bats are doing ok here on the other coast I think.