Our depressed bat population is possibly recovering

It was quite entertaining. The large outdoor light illuminating our south deck would, as darkness approached, attract hordes of insects all summer long—and the insects would attract
the bats.

They would swoop in unannounced, often mere inches from our heads, feeding enthusiastically as we sat relaxing on the deck after dark. The women would shriek, providing amusement for everyone, themselves included.

Then suddenly, nothing!

We live in a heavily wooded area in northern Nova Scotia but, even so, we haven’t seen a bat in maybe 15 years. We have two bat houses located in trees near our house that have remained unoccupied for the same time frame. What the hell has happened?

Well, a fungal infection known as White Nose Syndrome killed about 90 per cent of our bats—millions of them—across North America between 2011 and 2013. That is an uncommonly dramatic short term population decline in any species.

The fungus causes bats to wake up during hibernation, and with no insect feed available during winter, they starve and die—and the bat is one of the slowest reproducing animals we have, with some species producing only a single pup per year.

White nose syndrome killed more than 90 per cent of our bats between 2011 and 2013. It has killed millions across North America. Additionally, habitat loss from forestry activities has exacerbated the situation. The fungus infection has been spreading west, but the COVID-19 outbreak has been hampering monitoring efforts.

There’s good news, though. Researchers are cautiouslyoptimistic our bat population seems to be recovering from that fungus that nearly wiped them out a decade ago. A non-profitconservation group in southwest Nova Scotia is discovering growingbat colonies that point—hopefully—to population recovery.

One of the very few people monitoring the situation, Lori Phinney, a wildlife biologist with the Mersey Tobeatic Research Institute, says researchers were delighted to find the province’s largest known colony has grown to about 600 bats. In 2018, there were only about 380. Researchers like her have been closely monitoring these bat colonies since 2016 and each year they see what the peak number is. “We are definitely seeing more,” Phinney says.

At another site, researchers found 157 bats, up from 58 the previous year. Phinney is hopeful this is evidence of population recovery, but acknowledges it could instead be more bats gathering at fewer sites.

Why should we care? Well, quite apart from the common sense view that these days a population decline in any species is a concern, bats serve us by consuming tonnes of biting insects each summer. Phinney says they can each eat roughly 1,000 bugs an hour, which can also make them extremely valuable to the agriculture industry.

We have three main species of bats that hibernate here—the little brown bat, the northern myotis, and the tri-coloured bat. There are also four different species of migratory bats that spend their summers in the Atlantic Canada.

The public is being asked to contribute to monitoring efforts by sharing sightings of bats. They are asked to report where they saw the bat, the date and the time, and maybe what the bat was doing.

“With the help of the public reporting bat sightings, we can hopefully figure this out over the next few years,” Phinney says.

As to the apparent recovery: “We don’t want to get too excited, in case it’s a bunch of bats traveling from other areas and choosing these sites to raise their pups.”

The usual breeding season for the bat is in spring when temperatures are warmer. Depending on the species of bat, pups can be fully independent any time from six weeks of age. This is why so many species of bats are able to successfully reproduce several times in a given season.

The young hang from the furry belly area of their mother where they sleep and eat. It also allows them to have some warmth from her body.