At least for a few more weeks, the woods have ears (and eyes) along McIntyre Creek.
Yukon biologists have been monitoring the area this past summer with special microphones and trail cams aiming to get a better picture of which animals are using the area. In particular, special bat monitors have been set up along the creek, to track how bats might use wooded habitat.
“The Yukon Government has done quite a few surveys on ponds and wetlands around Whitehorse. With this question we’re more focused on the actual creek and seeing how bats use it, and if there’s specific characteristics, like soil, water, things like that that is really a draw to certain areas,” said Maegan Elliott, the conservation coordinator with the Canadian Parks and Wilderness Society (CPAWS) Yukon.
The McIntyre Creek project is a partnership between CPAWS and the Yukon Government, involving a number of scientists. The microphones will remain up until around the end of October, after which analysis on the data will begin.
Around the world there are 1100 species of bat, and five have been documented in the Yukon.
Most common is the little brown bat, but the big brown bat, northern bat, hoary bat and long-legged bat are also known to live in the territory.
With cool temperatures and short nights for most of their active season, the Yukon is not an ideal place for bats. They’ve also had to adapt to hunting in wooded areas and roosting in small crevices, trees or old cabins. Scientists also don’t know where they migrate for the winter.
Like foxes in Whitehorse, the bats around the city have learned to live alongside humans. Many people think of them as pests like mice, but Yukon government senior wildlife biologist Tom Jung compares their lives to grizzly bears instead – they can live up to 30 years and are devoted parents who raise very few young over their lifetime. Occasionally, they also conflict with humans, which researchers want to manage.
That lifespan makes them relatable to us, but their low rate of reproduction leaves them vulnerable to disease and habitat change, and the little brown bat’s population in the south has been decimated by an affliction called white nose disease.
While the disease hasn’t made an appearance yet in the Yukon, the more information we have about bat habitat, the better we can protect them, said Jung.
“In Canada, [little brown bats are] endangered mostly because of disease. It’s introduced to the bats in their hibernacula caves and other places where they spend the winter hibernating. Because they’re an endangered species, we’re trying to learn what we can about bats in the Yukon and boreal forests of western North America in general so that we can come up with conservation strategies,” he said.
High frequency microphones set up along McIntyre Creek could shed some light on these nocturnal mammals, allowing scientists to “eavesdrop” on their high pitched chatter.
“We don’t understand what they’re saying, of course, it’s not that type of eavesdropping, but at least we know where they’ve been and when,” said Jung. “We can also divide up the recordings we get, based on whether that bat was actively hunting or traveling.”
“So by putting out these detectors, we can understand what an important feeding area looks like for these endangered bats. Maybe it’s a couple of big old trees, or maybe it’s your pool in a stream, or it’s a small beaver pond. If we understand that, then we can place a value on it for bat conservation,” he said.
With special software, sounds captured this summer can be analyzed by independent researcher Brian Slough, who is able to detect variation in behaviour and species by the audio captured.
Around a dozen microphones have been placed in open areas along the creek every 100 metres. They are active shortly before sunset, and are sound activated during the night, when bats are most active.
The special bat detectors convert bat calls (or echolocation) to sounds that human scientists can hear. A bat call is from 20 to 200 kHz, far above the audible human range of 0.2 to 20 kHz.
In addition to the type of calls, Slough can also identify different species based on their calls.
“There are some larger bats that have lower frequency calls that are quite unique and stand out,” he said.
Since bats don’t stray too far from their roosts when looking for drinking water and insects, the levels of activity will be useful to identify which areas they use the most.
“The little brown Myotis or little brown bat uses edge habitats, mostly because they’re fairly open for them to fly around and try to find the insects but also close to cover,” said Slough.
“We’ll learn about seasonal habitat use, which I think probably changes throughout the summer. I think the bats will use forest interiors more at the solstice when it’s really bright, because they don’t like being out in the light and they’ll use open areas later in the season like passing over ponds or open habitats,” said Slough.
Contact Haley Ritchie at firstname.lastname@example.org