Little Brown Bats and Bat Boxes

Posted February 1, 2023

Comparatively to the summer months, winter seems to have stilled almost all signs of life. We may see it as desolate and barren, but it’s these tired, quiet attributes of nature that keep it healthy. Hopefully, as we visit the woods in these winter months, our surroundings remain quiet, otherwise, there may be room for concern. It’s not that we don’t miss our furry friends in the woods but if we were to start seeing them return too early from their hibernation cycles, we can assume that the reason is not because they miss us too but because they’re hungry.  

Little brown bats have a hibernation cycle that starts around October, where they will survive off of stored food reserves while they wait out the cold. They will reemerge in March to enjoy the abundance of insects that spring offers. In the last decade, there has been a horrifically dramatic drop in the number of bats that make it through hibernation. Catching a glimpse of one during winter is not the good sign that we’d like it to be; seeing a bat now means that it has run out of food reserves and will disrupt its hibernation cycle out of desperation to avoid starvation. But why is this happening? 

White Nose Syndrome (WNS) was defined in 2006 upon the discovery of the fungal infection that has plagued various species of brown bats across the US and Canada. The name stems from the appearance of a white, sugary-looking fungus that is seen on an infected bat’s nose and ears. This aggressive fungus increases a bats metabolism and as a result, stored food reserves can run dry as early as February. Unfortunately, WNS also irritates the skin and may form holes in bat wings, leading to dehydration. Bats that are forced to break from their hibernation don’t typically survive. WNS is credited for killing over one million bats a year and can devastate a brown bat population with a mortality rate nearing 100% at some sites. Since the introduction of WNS in Massachusetts, the state’s population of little brown bats has dropped to less than 1% of what it once was (Mass Dep of Fisheries and Wildlife). Little brown bats are affected disproportionately higher than other species due to their hibernation patterns of residing in cold damp caves and mines, an environment where the WNS fungi, known as Pseudogymnoascus destructans (Pd), flourishes. As of 2023, WNS is not a new threat but has continuously contributed to the most dramatic decline in North American wildlife in over 100 years. 

Fortunately, despite the grim circumstances, members of our community have taken it upon themselves to help anyway they can. One of the newest members of the Wareham Land Trust, Nick Perryclear, spoke to us about this issue briefly while joining us for a very cold and wet Trail Day back in early December. He has since then, donated four custom built bat boxes to be hung at various WLT properties in the hopes of providing dryer environments where Pd is less likely to affect little brown bats and therefore, aiding in the recovery of their population size. Using carpentry skills he learned at a young age, he tinkered with a couple designs until he settled on an ideal template. Changing materials from plywood to cedar, incorporating bat behavioral and nursing habits into the dimensions, Nick has done his research in order to give the little brown bats their best chance of success.  

Nick has been volunteering with conservation-based organizations for almost 37 years and speaks fondly of his time spent contributing to past restoration projects. As a vetted nature lover, he has done work with the Wildlands Trust for years, even back when it was known as the PCWT, (Plymouth County Wildlands Trust). We are eternally grateful to have such a devoted and knowledgeable member join our team and because of his contribution, we may see more of our furry bat friends scurrying around Wareham Land Trust properties by March of next year.  

Written by Emily Tramontano, TerraCorps Member

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