Bats and White Nose Syndrome

Bats are a misunderstood and unreasonably feared critter. Some species rid our skies of pest insects, while others pollinate crops and other plants. Bat poop (guano) is a rich fertilizer. Attitudes are changing as people begin to appreciate the ecosystem services bats provide but now they face another threat, White Nose Syndrome.

White Nose Syndrome (WNS) is a fungal infection that is destroying bat colonies at an unprecedented rate. The fungus Pseudogymnoscus destructans was likely introduced from Europe inadvertently. It thrives in the cold strikes bats when they are hibernating. Bats hibernate to conserve energy when their food source (insects or fruit) is unavailable, but the infection causes them to wake from hibernation. Being awake increases metabolism and other bodily functions, and the bats starve to death because of burning through whatever energy they had stored to make it through the winter. To answer your next question, “How does being awake kill a bat?”, most of the calories you need in a day are just to keep you alive- breathing, circulation, and the biggest energy consumer- temperature regulation.

WNS spreads from direct contact with an infected bat or from surface contamination inside a bat cave. People can transport the fungus from cave to cave, so spelunkers must decontaminate clothing, shoes, and equipment in between caves. 

Bats infected with WNS (National Park Service photo)

WNS has killed millions of bats in the eastern parts of the US and Canada is spreading west. Last year the first case was discovered here in Washington. Washington Department of Fish and Wildlife conducted a bat count a few weeks ago at Northwest Trek as the beginning of an effort to monitor bat colonies and WNS. A follow-up count took place this past weekend and I took part.

The goal is to count the number of bats seen leaving and entering the nest. Exits minus entries is the total number of bats seen. The tricky part is seeing them as it gets darker. I did OK with this until about 9:20. The freaky part is not seeing the bats until they are inches from your face, then they turn away at the last second, mostly to my left. I could their wings flapping as they passed by my head.

By establishing a baseline this year the state hopes to track population trends that could indicate colonies in trouble. This can be tricky, though. Bats sometimes tend to not roost in the same location night after night. For example, the site I counted was unmonitored in the previous count. The only reason I was posted there was because on the way into Northwest Trek we heard the bats making sounds inside the park entryway. My total for the night was around 60 bats. Other sites inside the park had a lower count than during the previous survey. It is possible that my site had an increase since the last survey, but that is unknown since no one counted there the first time. 

Me counting bats

In just six years since its introduction, WNS had killed millions of bats with a mortality rate up to 100% in some colonies, according to the US Fish and Wildlife Service. Fighting back will be a long process, but the key first step is monitoring. I am glad I had a chance to take part in the beginning of what I hope will be a successful fight. WNS info this week comes from the National Park Service, one of many partners in the search for a cure.

NPS: https://www.nps.gov/articles/what-is-white-nose-syndrome.htm

USFWS: http://www.batcon.org/pdfs/USFWS_WNS_Mortality_2012_NR_FINAL.pdf