Wednesday, May 19, 2021

It’s a bird, it’s a plane -- it’s a bat!

By Julia Craig, Masters student

View over Lost Lagoon, Stanley Park

Not every master’s thesis makes you feel like a comic book hero. Yet as I strap on my helmet and vest and emerge from my basement apartment, I feel like Batman suiting up and zooming out of the bat cave. Admittedly, there are some differences. Unlike Bruce Wayne, I lack a tragic back story. Oh, and I have to get by on a graduate student’s budget, rather than a billionaire’s. Ultimately however, we share the key qualities that make a comic book hero: we both have cool gadgets, a sweet ride, and a self-mandated mission to protect the citizens bats of Gotham City Vancouver. 

My stealthy mode of transportation is an eco-friendly batmobike. It features several high-tech gadgets including an ultrasonic acoustic detector and microphone on a pole (a lot cooler than it looks) and several low-tech solutions like audio dampening devices (which others might call “pieces of cardboard that block noise from my brakes”). The appearance is as striking as the batmobile--but for entirely different reasons. I often get odd looks from passersby. Maybe they’re also expecting a tinfoil helmet? But here function is more important than form: the batmobike lets me eavesdrop on bats.

Diagram of the Batmobike, drawn by Julia Craig

Like all biology students, I yearn to peek into the lives of animals. In this case, bats. I can’t actually translate bat conversations (yet), but I can tell which bats are present.

There are actually bats in Vancouver— as many as 8 different species, according to a preliminary study. Year after year, they return from a winter-long hibernation to their favourite summer roosts around the city; in tree hollows, abandoned buildings, attics and bat boxes. 

In fact, they’ve been here for generations. Much like humans, bats have long enjoyed living in river valleys, wetlands, and deltas, where there’s fresh water and warm nights. They become so attached to their summer residences that they have found ways to remain even as cities were built up around them. Indeed, they don’t have many other options in BC as much of their ideal habitat is regularly logged or developed for agriculture and industry. This loss of habitat is a primary threat for the many bats at risk in BC.

Protecting these species involves learning how to coexist with them—even in cities. First, we need to know what animals like about our cities to begin with. 

Although bats share our city and live amongst us, we know surprising little about them. Birds advertise themselves in plain sight. Bats, on the other hand, hide during the day. And when they emerge at night, they call at a frequency that people can’t hear. How they use the city is a mystery—for now.

Bats can be distinguished from birds at twilight by their agile and unpredictable flight patterns

Cue the batmobike. Using an ultrasonic detector and riding around the city at night, I hope to catch glimpse into where bats are. From other studies that monitored bat activity, I have some idea of where bats may like to hang out. For example, they often prefer one-stop destinations like ponds where they can easily grab dinner and a drink.

Vancouver, however, is one of the greenest cities in the world, with parks of all sizes, surrounded by a bay and a river, with greenways and trails that run through or by them all. Will bats use these varied landscape features for foraging or as connections to other parts of the city? Or will they stay only in the most “natural” areas? Are there differences between bat species: do they form cliques, with all the artsy little browns hanging out by the river or sporty California myotis foraging by the beach?

These kinds of studies (called “mobile transects”) are often done with cars, but I have chosen to use a bike as it is better suited to the city. With a bike, I can transverse the city on its many greenways, roll through parks on gravel paths, and ride through forests on dirt trails, or by ponds on golf courses. In theory, I will get a pretty complete picture of where bats are in the city. Perhaps batmobikes will become more common practice in the future, with enough velophile grad students!

Stay tuned to discover with me the secret lives of bats! 

Creative Commons Licence