Bernie the Bat

We’ve been in Tokoroa for two weeks now. I really should’ve explained what we’re doing here a while ago, but I was trying to wait until we actually caught a bat. By Monday night I’d resigned myself to posting to the blog even though we hadn’t caught a bat yet when WHAM-- we got one. Ever since then, we’ve been quite busy trying to keep up with it (I’ll explain later).

So what exactly are we doing here? I am planning to begin graduate school in August 2007 for a Ph.D. in ecology. I’m especially interested in bat ecology, so when Matt and I decided we were coming to New Zealand, I contacted some bat researchers here. They put me in touch with Kerry Borkin, a grad student beginning her Ph.D. research who was looking for volunteers. I got in touch with her back in May and arranged for us to work with her for a few months. So now we’re in Tokoroa living in a house with Kerry and assisting with her research.

New Zealand has two species of bat: the long-tailed bat and the short-tailed bat. These are New Zealand’s only NATIVE land mammals. In spite of what their common names would lead you to believe, the long and short-tailed bats are not closely related at all. The short-tailed bat, with few native predators, is actually quite quadrapedal and forages on the ground in addition to flying. Kerry is studying how the long-tailed bats use the huge exotic pine plantation surrounding Tokoroa. This involves identifying where they are roosting and foraging within the forest.

For the past few months, Kerry has been using Automatic Bat Monitoring units (ABMs) to record bat activity in different parts of the forest. The ABMs record the bats’ echolocation calls that are made audible to us by a bat detector. You can also just use a bat detector (separate from an ABM) to listen for bats. Last Wednesday, Kerry’s advisor from the University of Auckland came down to train the three of us how to catch bats. Kerry is just beginning her research so she was learning with us. On Wednesday and Thursday nights we set up mist nets near a pond where an ABM had recorded a lot of bat activity. We listened for them with bat detectors and used night vision goggles to watch for them, but it was much more fun to use them to look at the stars. The bats seem to be active in those areas until about midnight, so we closed up the nets and headed home around then. No bats in the net on Wednesday.

This picture is pretty blurry because it was taken by holding the camera up to the night vision eyepiece, but I think you get the idea.

On Thursday night, Kerry invited a man who works for the forest company to come look for bats with us using his thermal vision camera. That’s right, we’re talking night vision and thermal vision like right out of the first person shooter video games. When you focus the camera on something, it will tell you the temperature of the object. This camera is INCREDIBLY cool. So incredibly cool that it made night vision seem quite boring.

This is a picture of me in thermal vision. Again, it’s blurry because we just held the camera up to the eyepiece. The camera operator might send us some of the better images he captured, in which case we’ll try to post them. You can see from the scale on the right that my nose is the coldest part of my face.

These cameras cost over $100,000, but the forest company uses it at their paper mill to detect leaks and equipment that isn’t running properly. Apparently it saves them a pretty penny to be able to pinpoint problems precisely with this precious piece of picture producing paraphernalia. We could see the bats swooping down to the water with our thermovision. Unfortunately, we didn’t catch any in our nets.

On Friday night we put up the mist nets just down the road from our house. Only one bat was detected with the bat detector and it didn’t visit our mist net. Around this time, we learned that someone else did her Masters thesis on bats in this forest and never caught a single bat. Yikes. That would be a real bummer. Saturday night we tried catching down the road again and didn’t even hear a single bat on the detector. Sunday night was crappy weather so we had the night off.

Monday night we set up on the road again. We put up a 9 m high mist net (I like to call it the Big Rig) across the road and a smaller mist net nearby across a trail. The three of us were taking turns watching the two nets and waiting in the car when it happened- a bat flew into the mist net! We untangled the bat, bagged it, took down our nets, and brought everything back to the house. When you catch a bat the night is just beginning. We took measurements, collected hair and poop, and named him Bernie. Most importantly, we glued a wee radio transmitter onto its back. This allows us to track it, and makes sure that none of the cool bats will play with it at recess.



Not a bad shot of him, but unfortunately you can’t see his little eyes. I promise he has some.


Tiny little thing, isn’t he?

At this point, things get complicated. We had two vehicles and two radio antennae. All kinds of things can go wrong at this point. Once you release the bat, the radio transmitter could fall off and that’s the end of tracking that bat. Or the bat could fly a completely different way than you expect it to and you could lose the signal in a matter of minutes. Thankfully, we got lucky. Matt drove and radiotracked in one car while Kerry drove and I radiotracked in another car. We were able to track the bat for an hour! Not bat at all for our first bat tracking.

There are two things to be determined from radio tracking. The first is a bat’s foraging path. More importantly, it can be used to find roosts. So on Tuesday (in daylight), we drove around the forest trying to pick up a signal to no avail. No leads yet on where this bat is roosting. Theoretically, we have about 2 weeks to find it before the battery on the transmitter dies.

Carrie