Deadly fungus that could decimate Island bats has reached BC

The biggest threat to our bats doesn’t kill them directly. Instead the fungus Pseudogymnoascus destructans wakes them up from hibernation as it grows on them, and forces them to burn so much of their stored winter energy on cleaning it off that they don’t make it to the spring.

Called white nose syndrome (WNS) for its distinctive appearance on bats, it emerged in New York state in 2006 and has killed millions of bats in eastern North America, wiping out 90% of many affected populations. Prior to this year, its march west had reached Saskatchewan and Washington state. Now, after its fungus was found in bat guano in Alberta in January, it has been confirmed in guano in southeastern BC.

The province announced the Grand Forks discovery on April 4, warning that the disease has driven three Canadian bat species onto the endangered list.

This is a turning point that local conservationists, experts, and enthusiasts have dreaded for years. Fears first surged in the South Island with the 2016 discovery of WNS in Seattle, 2,000km closer than cases had been seen the previous year. As it spread in Washington state, WNS got to be less than 100km—within the travel radius of most Canadian bats—from Greater Victoria.

Migration could bring WNS to Metchosin colony this month

Grand Forks, at least, is still more than 350km away. But the discoveries there and in multiple parts of Alberta appear to signal increased spread in the west, and mark the threat’s advance toward the Island from the east as well as the south. More bat colonies in BC with WNS mean more possibilities that it could be brought to the Island during migration.

The Island has nine of BC’s 17 bat species, and the major roost at the Metchosin community hall attic houses Yuma bats and little brown bats (which have both been detected with WNS across the water in Washington). The hall roost, revealed to the public in 2015, brings together post-hibernation bats from across BC every April.

Bat conservationists ask that the public report any bats seen dead or sick, and to report any colonies on your property as well as the date its bats become active. Spring is when bats emerge, but emergence earlier than usual in spring may be a WNS indicator. See the BC Community Bat program site to report, or to contact your region’s program coordinator.

Probiotic could help, but isn’t ready yet ‍

Not all bats are vulnerable to WNS but many local ones are, such as those in the Metchosin Community Hall. There remains some hope that BC bat populations may at least be hit less quickly and severely, because their roosting colonies are not as large as eastern ones.

BC may also be able to resist WNS by preemptively spraying bats with a region-specific probiotic that has been shown to slow WNS growth on bat bodies. But, even if it is effective enough, that spray will not be ready this year, and so Greater Victoria’s furry fliers remain highly vulnerable.

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Read more about the Metchosin community hall bats and some of the locals looking out for them in Capital Daily’s bat feature .