Going Batty

International Bat Week, a global celebration of the world's most misunderstood mammal, fittingly comes to a close tomorrow on Halloween. To celebrate, let's take a trip down memory lane to that time five years ago when I helped with a bat colony count. It was late summer in 2017. I was just a few weeks away from leaving the Northwest and returning to my native Pennsylvania. I was invited to a pot luck for volunteers at Northwest Trek, a wildlife park in Eatonville, WA. I'd worked with them doing amphibian egg mass surveys for the state and nature mapping for Nisqually Land Trust. There was also a bat colony count happening that night, and I was asked if I would like to join. Of course I said yes. After white nose syndrome was detected in Washington, the state fish and wildlife service wanted to colony counts to establish a baseline population for monitoring purposes. Having worked on other conservation projects with Northwest Trek it was only natural that they would ask them to partner up again. And it was a no-brainer for me to get in on the action. After eating, we took an extended afterhours tram ride through the free roaming area to see the deer, elk, bison, moose, mountain goats, and bighorn sheep who don't know they're lving in captivity. There's nothing wrong with a little extra time hanging out with our animal friends. Afterwards, we returned to the park entrance. I was supposed to monitor the comings and goings at a bat box inside the park just inside the entrance. All I had to do was count how bats flew out and how many flew in, until I couldn't see anymore. Ins and outs, then subtract and the difference is my count. Very simple. But the bats had other plans for the night. Before we even got inside we could hear bats moving around inside the roof of the entrance. I never made it in. Instead, I stood outside the entrance counting bats. I watched as a little bat would drop down from the roof and gain altitude as it moved towards me. I only ducked once or twice. It was just instinct. I knew they wouldn't hit me. I figured with their echolocation they could tell where I was long before I saw them. I could hear theirs wings flapping and feel the breeze as they zipped past my head. At the end of the night, all the participants gathered to turn in their tally sheets. The counting station at the entrance, which wasn't on the list at the beginning, and was almost an afterthought, turned out to have the highest count of the night. I don't remember how many bats we counted collectively, or what my total was. It was a great night and I hope we collected important data. I'm forever thankful I was able to be a part of it.

Cave Life

This week is Cave Week, so to celebrate we're going spelunking to see what critters we can find. In addition to all sorts of whimsical formations, caves host a surprising amount of life. There are trogolobites, which live full time in caves; trogolophiles, which live in a cave but can also survive outside; and trogoloxenes, the part time cave denizens. You can encounter insects, fish, birds, mammals, plants, fungi, and others. Because there is very little natural light, many of these species are adapted to live in darkness; some don't even have eyes.

Whimsical cave formations

The first cave critter that comes to mind is a bat. Many bats roost in caves because they are cool and dark during the day, making it easier to sleep. Caves make a great place to hibernate over the winter. A constant temperature that is above freezing is an obvious plus, but it's cool enough to trigger the hibernation process. Other cave mammals include bears and jumping mice.

To the bat cave! (National Science Foundation)

Plants are a rare find in  caves because they need sunlight for photosynthesis. I saw ferns growing in a cave under a ceiling hole that opened to the surface. Much more common are fungi, which thrive in dark, damp conditions. Most important among them is Pseudogymnoascus destructans, which causes White Nose Syndrome in bats. It is devastating bat colonies across the US and Canada, and enjoys the cool temperatures while the bats hibernate.

White Nose Syndrome affecting these bats (NPS)

Cave fish are interesting little critters. Nearly all lack eyes and skin pigment. With no light to see by, there is no need to camouflage or stand out, so they are likely to be white or light colored. Unable to see their food, they find it by sensing movement in the water. What exactly do they eat? Since plants, the base of the food chain can't really live in a cave, anything in there either needs to go outside for good or eat whatever gets brought in. Cave fish eat detritus that washes in during rain events. Other critters get by on dung, the leaving of larger animals that way out.

Blind cave fish (NPS, Rick Olsen)

Cave Week runs through this weekend. Find a cave near you and check it out. Spelunk safely. Use the buddy system, carry at least three light sources, and make sure someone knows where you are going. Don't disturb any wildlife and make sure clothing and equipment are thoroughly cleaned before entering another cave. This helps prevent the spread of White Nose Syndrome.
This week's information comes from the National Park Service and National Geographic.

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