By Holly Long
When the Canadian Wildlife Federation partnered with the Ministère des Forêts, de la Faune et des Parcs du Québec (MFFP) to aid in their understanding of bat populations within the Outaouais Valley, I jumped at the chance to study these amazing creatures. We assisted the MFFP with their research by travelling specific routes within Gatineau Park in search of bats.
How Do You Track a Bat, Anyway?
Since bat echolocation occurs beyond the scope of human hearing, we utilized bat detecting technology in order to hear the bats along the roadways. Generally, traditional bat detecting equipment can be complex to operate so as a new user I was excited that CWF was equipped with a more user-friendly alternative. Phew! Truthfully it was pretty simple to use. The Echo Meter Touch module by Wildlife Acoustics plugs directly into an iPhone and is used in combination with an app that pairs with the device. . Each time a bat call is picked up by the device, the software runs an analysis and shows the most likely species for the bat and translates the frequency to one that is audible to the human ear.
Adventure Awaits: On Route
Late one August evening, versed in the use of our new equipment, myself and three researchers at CWF, Carolyn, James, and Brandon, sought to complete our first night of surveying in the park. To comply with the MFFP standards for the bat surveys, we needed to complete two driven loops of our given route from Pink Lake via the Promenade Champlain to a given point in Kingsmere.
Armed with our equipment and readiness for the night’s events, we jumped into our vehicle and to our enthusiasm, the first recording of the night yielded a result. The spectrogram bounced up and down on the detector, alive with colour, as what sounded like a symphony of tiny metal and glass objects clinking together emitted from the speakers of the device. A small box popped up on the screen reading, “Big Brown.” Immediately upon Carolyn drawing our attention to the triggered identification, Brandon and James fiddled with the spotlight and pointed it towards the open night sky. We all popped our heads out of the car windows and focused on the canopy gap created by the roadway, searching the space for a flying figure, but to no avail.
A mere two minutes later, the device began to pick up the sound of another bat. Again, the screen read, “Big Brown”. We pulled over to the side of the road and Brandon shined the spotlight up into the night sky. There it was, flying overhead with quick and erratic wing beats, our first bat sighting of the survey. Being able to not only hear the bat call on the detector but also see that same bat flutter above us was an unforgettable experience.
We continued the survey into the late hours of the night. It became apparent that the roadways were a hot spot for bat activity the further we travelled. Soon we were stopping almost every minute to try and spot a bat flying in the sky as the detector sounded with the same clicks and clinks as before. Sometimes we were even able to witness multiple bats flying, one after another, trolling the opening in the canopy for a midnight meal.
The Results Are In!
The cast of characters. At the end of the night we had accumulated an abundance of data both written and on the bat detector. Big Brown and Silver-haired were our two most identified bats of the night. The detector also identified other species such as Hoary, Little Brown, Eastern Red, Tricoloured, and Northern Long-eared.
We hear you loud and clear. The Big Brown and Silver-haired bats seemed to have the loudest calls exuding from the detector, with other species like the Hoary bat and Eastern Red having quieter calls. We hypothesised that this was because these bats were possibly not using the roadways as much as the two other species were to search for insects. Thus the sounds were being detected from greater distances and potentially becoming muffled in the process.
Sizing them up. When we had the opportunity to see them in flight, the Big Brown and Silver-haired bats also appeared to be a little larger than the other species.
Our Second Adventure Begins: On Foot
The roadway surveys left us wondering if there was a bias in exclusively conducting surveys on the road, if different species really did prefer to feed within the canopy and if gaps within the woods would yield the same detection results as the canopy gap created by the roadway.
And so we set out on foot, walking trails within the park that ran close to parallel along the original roadway route. The walking surveys did not yield anywhere near as many results as the original surveys did.
The Results Are In!
The cast of characters. The bats we identified on the detector time and time again during our walking surveys were the Silver-haired and Eastern Red Bat. Hoary bats also accounted for a sizeable amount of the detections as well.
Open vs. closed canopy. We found that each time our walking path would cross the road the visual and detector observations increased, but when we were walking through heavily forested areas, the results were limited. Gaps in the forest canopy and areas with open water along the trails produced more identifications on the detector then the heavily tree covered areas did. However, the sounds generated from the device were still much quieter than those produced while walking along the road.