White-Nose Syndrome: the silent bat killer.

Tri-colored bat with visible signs of WNS. Photo: US Fish and Wildlife Service, Flickr creative commons.

Tri-colored bat with visible signs of WNS. Photo: US Fish and Wildlife Service, Flickr creative commons.

Although bats are not everyone's favourite animal, they're important for keeping our ecosystem in check. A new bat disease is invading Canada and causing some bat species to decline.

There are 19 species of bats in Canada - three of which have been recently added to the List of Wildlife Species at Risk in Canada. In only a few years, these bat populations have decreased by 90 per cent.

The Little Brown Myotis, the Northern Myotis, and the Tri-colored Bat are all endangered due to White-Nose Syndrome (WNS), an extremely deadly and highly contagious disease.

The disease is caused by a fungus, which grows on the exposed skin of bats while they hibernate in mines and caves during winter. A white substance grows on their ears, wings and muzzles, affecting their muscle tissues and blood vessels.

Bats affected by WNS are likely to die from starvation and dehydration as the disease causes them to wake up frequently during hibernation, depleting their limited electrolytes, fat and stored water resources.

The disease was first discovered in North America (New York) in 2006, and its origin has been traced back to Europe. It spread to Canada  around 2010 and has caused a rapid decline in the three bat populations ever since.

According to the Government of Canada, the fungus can be spread by contact between bats, by their environments, or by people carrying the fungus spores on clothing or equipment.

It may seem easy to dismiss such a small mammal that most of us never see, but they  provide important pest control services. They eat large amounts of insects that would otherwise damage forests and crops, playing an important role in a healthy self-sustaining ecosystem. Bats control the pest population, reducing our need for insecticides.

Meanwhile, trees being cut down and a reduction in barns and attics has lead to habitat loss for bats. Wind turbines are also a major problem, resulting in approximately 600-900 thousand bat mortalities per year.

Although it may seem hopeless for these bats, there are some ways that people can help. If you plan on entering any caves or inactive mines, make sure you take proper decontamination precautions that effectively destroy the spores of the fungus. This will ensure that you don’t spread the disease. When possible, avoid visiting caves and mines in winter months when bats are hibernating.

You can also make a donation to the Canadian Wildlife Federation (CWF) or buy one of their “Keep Bats Undead” t-shirts. CWF-branded bat boxes are available to purchase, but if you would rather build your own box, simply download the instructions from their website. Bat boxes provide a safe haven for bats in the spring when they come out of hibernation.

You can also plant flowers and shrubs that encourage moths, an important food source for bats. If you find a bat, please leave them undisturbed. Supporting forest and wetland conservation is important, and caves and mines must be protected as well.