Tuesday, December 4, 2012

Needed: Batman-proof bat caves

Today you're hearing from
Eric Schrading, a biologist
in our New Jersey Field Office.
Read more from Eric.
Sure, some people either don’t understand or don’t like bats.

They make up fearful stories about bats and their habits and associate them with villainous creatures such as vampires. But let’s lay down some facts about these truly unique and wonderful creatures.

Bats are the world’s only flying mammals. They can consume nearly one-third their body weight of insects in less than half an hour (that’s a lot of agricultural and forest pests, mosquitoes, and stink bugs), and they are also one of the only animals that are associated with one of America’s most popular superheroes: Batman.

I’m not here to blog about the pros and falsified cons of bats, but I do want to tell you about Batman-proof bat caves. First I have to tell you a little about bat ecology. Bats spend their springs and summers in forests, streams and fields foraging on insects. But when it gets cold in the winter, and their insect diet disappears, some bat species take their party south, and others begin a long hibernation in caves and mines.

Indiana bats. Credit: USFWS/Ann Froschauer.
In New Jersey, these hibernation spots are more often in mines. A variety of iron ore mines in the state were constructed in the late 1700s for the Revolutionary War and for strengthening a young nation, and when they were abandoned, the mines began providing winter refuge for a variety of bats, including the endangered Indiana bat (Myotis sodalis). These bats and others survive the winter by gathering in large numbers in these mines to take advantage of stable temperatures and humidity.

Now, here’s where Batman comes in.

Batman, along with other humans (cavers, spelunkers, inquisitive teenagers or explorers), enjoys searching and spending time in caves and mines, whether to hide the Batmobile or to check out stalactites and stalagmites.

A gated cave in New Jersey. Credit: USFWS/Eric Schrading.
The problem is that any disturbance to bats during their hibernation can wake them up. Bats during hibernation operate on a very thin line between survival and death. Any disturbance, no matter how quiet Batman is -- even if he's just using his bat-light -- can wake bats up, causing them to use valuable energy reserves (remember, no food available all winter long). Just one disturbance can cause them to burn up a month’s worth of fat reserves. This may be the difference between surviving the winter... or not.

Some mines need protection to provide much-needed hibernacula or winter refuge for lots of bats. So wildlife agencies, including U.S. Fish and Wildlife Service and its partners, sometimes cover the mine or cave opening. This keeps Batman out (sorry Batman, but as a wealthy superhero, you have other options), but how do you allow bats to move in and out?


The U.S. Fish and Wildlife Service is working with our partners to help make sure that Batman (and other cave explorers and researchers) aren’t inadvertently making the problem worse by spreading the fungus that causes white-nose syndrome.

We have developed decontamination protocols to reduce the risk of transporting the fungus on our shoes, clothing and gear, and some areas have closed caves and mines to protect bats. It’s important for everyone (including Batman) to contact their local land management agency before visiting caves and mines to make sure they are open for exploration. More

The answer is large bars welded together in the form of a gate. Yes, a bat gate… sufficient enough to keep Batman out (with his significant strength and utility belt that includes sawzalls), but with enough openings to allow bats to come and go and to allow natural temperature and humidity in the mine or cave.
So there you have it, a bat gate… Keeps Batman out, but allows the bats to come and go as they wish.

These projects are even more important now that many bat species are being decimated by white-nose syndrome at many of these hibernacula sites. This fungal disease has killed more than 5.7 million bats mostly at hibernacula sites in more than 19 states and four Canadian provinces – making the importance of reducing any mortality associated with Batman even more important.

Read another post on gating caves in West Virginia.

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