As the weather gets warmer, the province’s reduced bat population will soon be coming out of hibernation, and they could use a little privacy as their winter sleep nears an end.
Wildlife expert Andrew Hebda says the bats should still be hanging out at the hibernation sites at the moment, waiting for the changes in barometric pressure that come with spring storms, coinciding with temperatures going up and the emergence of insects.
“This is a time really to keep away from places you think they’re hibernating,” the curator of zoology at the Nova Scotia Museum of Natural History said on Monday. “So this is really sort of a critical period where normally they’re going to be running a bit low on energy even if there’s no disease present.”
Nova Scotia’s bat population has been dramatically affected by the fungal infection known as white nose syndrome. The disease causes the bats to wake up from their hibernation early, resulting in them burning through their brown fat reserves.
“And they’ve only got so much there — probably enough for about a dozen awakenings through the winter, which is a normal thing — and if they use up all that brown fat by mid-winter and they have none left, then of course when they wake up they need energy so they go out and that’s when people would see them flying around in January or February in the snow. Of course, there’s no food, so those would die.”
Hebda said the ones that have made it through the winter will emerge probably within about a month if the weather continues as it is, although there could be variances depending on the region of the province.
“We need to get that night temperature up above around four degrees,” he said. “We need that for a period of about a week to 10 days. Once that happens, the insects come out and in amongst the first ones you’ll see are mosquitoes and the like. Then if the bats are out there, they can forage.”
This is probably the most dangerous time for people to be disturbing them in their hibernation sites because they really need that last bit of energy to be able to get them ready for spring time, he said.
Hebda said some of the big old hibernation sites that most people may be familiar with are pretty well completely depleted and experts suspect the balance of the population is now left in smaller sites.
“I suspect we’re probably running about five per cent of the population remaining but that’s probably bottoming out at that point. We’ve certainly had a couple of areas of high activity last year, which is a good sign,” he said.
“I’m always hopeful that if the disease isn’t spreading . . . then essentially what we considered relatively minor sites for hibernation now may become much more important in sustaining the population. Will they completely crash and disappear? Probably not. But our kids and grandkids probably won’t see the kind of numbers that we used to see.”
He saw no reason to suspect the winter was difficult on the remaining bats. A relatively mild autumn would have allowed them to build up a good fat supply.
“If you had a nursery colony in your house and it was active last year, it will probably still be active this year, in which case take advantage to see what’s there,” Hebda said. “Don’t get rid of them. If you have an issue, certainly, I strongly suggest you get in touch with your local DNR office so they can advise you as to how to work with them.
“The important thing is that if people do see any is to report them.”
Bat sightings can be reported through www.batconservation.ca.
You can also report them to your nearest regional offices of the Nova Scotia Department of Natural Resources or the Mersey Tobeatic Research Institute’s bat and rare species toll free line at 1-866-727-3447.
“Certainly, knowing where they’re active is very, very useful and that’ll help us identify where there’s a lot of nursery activity going on right now. That’s always positive and then we can work on the education piece.”
Hebda said bats used to be much more widespread in the province and the biggest site used to have about 17,000 in it. That dropped to around 300 about three years ago, he said. He suspects it’ll likely stay that way.
“So, in other words, those sites probably wouldn’t be useful but there are a lot of other places that we’re not aware of or that we can’t access that they probably have been using and those may be secure.”
There are a couple of sites that he’s keeping an eye on. He’s also keeping their location secret.
“I’ve found in two of the sites I’ve been watching, we’ve had comparable numbers now to what we had 15 or 20 years back, so there’s sort of patchiness in where they’ve over-wintered and patchiness in where they have those nursery colonies and where they’re foraging. And that’s always a positive thing.”