A Night of Radio Tracking

It’s late May and the bat team is finally ready to transition from months of planning in the office, to finally getting out into the field and putting our plans to action. We’ve got an ambitious summer ahead of us starting with attempting to radio track northern myotis. Radio-tracking a target species is always a gamble, as there’s no guarantee you’ll catch the species you’re looking for. This poses our team a few problems when it comes to making sure we work our minimum hours required in a shift, while also trying to avoid working double shifts.

Jasmine and I meet up with the trapping team in hopes of being able to radio tag a northern myotis (Myotis septentrionalis). We’re all a bit on edge. The ‘Bat Boss’ is a bit nervous, as we’ve never attempted to catch these bats this early in the season. At this point, it was a waiting game.

It’s time to check the mist net and we see a bat!!!! Except as we get closer, we see it’s a big brown bat. It’s still exciting, but it’s not the bat we are hoping to catch. We take him out, process him, and let him go and await the next net check. Round two, we walk up to our nets and see another bat… it’s a northern!!!! We lower our nets as fast as we can before the bat can escape on its own. I manage to secure the animal and gently untangle her. We then take her measurements and determine that she’s big enough to carry the weight of the transmitter. We get her all prepped, and then glue the transmitter onto her back. We use ostomy glues – designed for humans – which naturally wear off and allows the bat to drop the transmitter after a few days. Then we release her and Jasmine and I are off!


We have a long night ahead of us, as our goal was to follow her all night until she roosts again at dawn (and it was only 22:00). One of the challenges we always face when radio-tracking is how easy it is to lose the bat. We’re at a disadvantage because we can’t fly, so a distance that takes the bat seconds to get to, can take us 20 minutes and by the time we catch up, the bat could have decided to hightail it in the opposite direction. Naturally, we lose the signal, so we wander on the trails back and forth, and finally pick her up again somewhere off in the distance. Luck is on our side, and we find that she hasn’t moved for a while, so we chance settling down, and pulling out the hot cocoa and marshmallows to warm us up on this cool spring night.

Jasmine keeping track of the signal from a high vantage point

We stare off into the horizon and notice that the signal is only detected through the small gap in the trees and the strength of the signal was suggesting the bat was further afield than we had anticipated. I pull out my map and see that there’s a whole greenspace area ahead, so we decided to head back to the car and see whether we can hone in on her location. When we get back to the parking lot (around 1:00AM) we see the trapping team was still there! They had been locked in the parking lot and the gate code they were given wasn’t working and no one was going to be by to open it again until 7:30AM.


Fieldwork often requires a lot of adaptability and ability to think on your toes. The trapping team was busy trying to work out how to get home… meanwhile, after spending months playing virtual escape room games with friends online, I’m writing out the 16 possible code combinations (assuming that the numbers provided were correct). First number input- CLICK- lock pops open- adds “Code-breaker” to résumé. Trapping team is grateful and make their way home.

I’d like to say it was smooth sailing the rest of the night, but that’s not how fieldwork goes. We manage to drive to the greenspace and confirm the bat was in fact using this area. We were very excited about this as we had assumed the northern myotis travelled more extensively in this area, but never had any proof until now! We study the area and determine some other streets we could drive down to attempt to surround her and potentially “triangulate” (identify precise location of bat using multiple GPS points and compass bearings) the location of the bat. This was where we discovered my key fob battery had died, so the only way to get back into the car was manually inserting the key. Except, for some reason, this always triggered the car alarm, which I imagine the local residents would not appreciate at 1AM. The alarm would not stop until the car was started… The rest of the night we were diving in and out of the car to minimize the noise. To make matters worse, we had also left our clipboard with our tracking data on the roof of the car, which naturally fell off once we started moving. We then had to retrace our tracks and luckily, found it right in the middle of a suburban road.

Thankfully, that was the gist of the excitement. We then determined that there was no way to access the greenspace where the bat was located on foot, so we settled into the car, stuck the radio-tracking antenna out the window, and tracked the bat from the warmth and comfort of the vehicle, while listening to some music.

Jasmine (left) & Melissa (right) keeping tabs of the northern myotis from the parked car

The bat stayed in the new area until dawn. We stretched our legs, wandered along the path and enjoyed the dawn chorus, as the birds started waking up for the day. Looking out into a pond we saw some splashing but couldn’t tell whether it was a grebe-like bird or an otter playing around. All in all, it was all very serene, until 5AM came and our bat had left the area to settle for the day. We get back into the car and drive back to where we had originally caught her, and sure enough, she’s there! We track her to the roost (not before she gave us the runaround as she was acutely aware of our presence), and then call it day! Just in time for morning Toronto Westbound rush hour. Usually, we’re on foot all night tracking bats, but this bat was very kind to us, and not only was she only accessible by vehicle, but she also stayed in one spot the entire night. For sure an excellent way to ease us into the start of our field season.

Written by: Melissa Donnelly & Jasmine Anthony