In Pursuit of Canada’s Hottest Bat

In Australia, we may not think of Canada as a particularly warm part of the world but nestled in the Fraser Valley in British Columbia’s Coast Mountains, Lillooet may be Canada’s hottest town.

Although it is home to 13 of 15 Canadian bat species, summer temperatures in these parts of the Fraser Valley can exceed 45°C. This made Lillooet the ideal location for the “Hot Bats” research team, led by Dr Zenon Czenze from the University of New England, to study how bats deal with heatwaves.

Beautiful Lillooet on a relatively clear day (left) and on a particularly bad day for smoke from the surrounding wildlife (right)
Beautiful Lillooet on a relatively clear day (left) and on a particularly bad day for smoke from the surrounding wildlife (right)

The international research team included UNE PhD student Ruvinda de Mel and researchers from The University of Regina, Wildlife Conservation Society Canada, the University of Winnipeg, and the University of Northern British Columbia (UNBC).

This motley crew was brought together by their passion for bats, science, great company and, to a certain extent, Dungeons & Dragons.

Despite the size of the research team, the project wouldn’t have been possible without a critical collaboration with local ecological researchers at Splitrock Environmental and St’at’imc Government Services.

Members of the Hot Bats research group
Members of the Hot Bats research group

We aimed to ask questions about the roosting habits of bats (where? when? and why?) and how they regulated their body temperatures during high temperatures and heatwaves.

To answer these questions, we first needed to capture bats and so we ventured out into the field night and day, setting up mist nets and harp traps strategically across flight paths in forests and across narrow waterways. Once captured, we glued tiny temperature-sensitive radio transmitters (about the size of a raisin!) on the back of the bats and set them free.

Harp traps (left) and mist nets (right) used to capture bats

These transmitters allowed us to use antennas to locate the bats’ roost sites each morning and record their body temperature until the transmitters naturally fell off. Tracking bats is no easy task, and the sight of us early in the morning, wearing high-vis vests, walking about town or scrambling up mountains with antennae held high led to many curious people asking what we were up to.

We quickly became known as “the bat people”.

When accessible roosts were located, miniature data loggers were placed within the roosts to gather data on the roost microclimates. Even with local community members helping to identify and access bat habitat and roost sites, we faced a few challenges.

Some days, radio tracking was regularly foiled by a myriad of different reasons ranging from high-voltage power lines to black bears that fully understood, and exercised, their right to not give way to bat scientists.

Other days, the bats simply played, and won, “hide from the researchers”.

Checking out if anyone is home inside a bat box (left) and a local black bear (right)

However, the major issue was the threat posed by multiple forest fires burning fiercely around Lillooet that loomed large for almost the entire length of the project.

Despite all these challenges, the project was hugely successful, and we uncovered some interesting details about the ecology of the bats.

We learned that the roosting habits of bats is more variable than expected and although we found bats preferred living in tree hollows, many favoured human-created structures, such as old barns and in the crevices of houses.

Interestingly, the largest colony of Yuma myotis (Myotis yumanensis) we came across inhabited the small gaps on the outside of a petrol station!

Near the end of the summer, and working closely with Chief Bonnie Adolph, UNBC Master’s student Tina Watters and Vivian Birch-Jones, the Secretary of the Lillooet Naturalists Society, organised a community bat night.

Hot Bats team member Tina Watters organised a community bat night that the team all helped out with

Our goal was to engage local community members about the bats in their region and the event was a resounding success and clearly demonstrated how enthusiastic the community was to learn about and protect their bats in an ever-warming world.

The escalating number of forest fires in British Columbia each year stands as a testament to the disastrous effects of climate change, and the data we collected will help to develop conservation strategies for British Columbian bats.

The roost site selection data allows managers to identify and prioritise critical natural habitats for the bats when planning future protected areas. Artificial bat houses are abundant in many a garden in Lillooet, and our roost microclimate data can help inform community members how best to create bat houses that cater to the bats’ preferences.

The Hot Bats team expects to return to Lillooet and continue this research and our community partners have promised a cheerful and warm welcome back.