Tri-colored bat (Photo courtesy of Rick Reynolds, Wildlife Biologist, Virginia Department of Wildlife Resources)

This blog post was developed with insights from Mark Ford, Associate Professor at Virginia Tech’s College of Natural Resources and Environment, whose extensive research on bat ecology and conservation has been instrumental in advancing our understanding of bat populations across Virginia. 

As spring arrives, Virginia’s bats are on the move. Some are waking from hibernation, while others are returning home. Whether they’ve spent winter in caves or stayed active in warmer regions, this season is critical for their survival and recovery. 

Keep reading to learn more about how bats survive winter, what challenges they face and how you can support their return. 

Hibernation or migration 

Little brown bat (Photo courtesy of Rick Reynolds, Wildlife Biologist, Virginia Department of Wildlife Resources)

Of Virginia’s 16 bat species, only nine are true hibernators, including the little brown bat. These species spend the winter in caves and other sheltered spots. Others, like the eastern red bat, migrate south and remain active during the colder months. Some coastal Virginia species, such as the Southeastern Myotis, may enter short bouts of torpor (a short-term, controlled state of reduced metabolic activity, heart rate and body temperature) but stay active during warm spells. 

Coming out of hibernation 

Big brown bat (Photo courtesy of Rick Reynolds, Wildlife Biologist, Virginia Department of Wildlife Resources) 

As temperatures begin to rise, Virginia’s hibernating bats start to stir. While most remain dormant until conditions are consistently favorable, an unseasonably warm week can occasionally prompt early activity.  

Some species, like the big brown bat, may even switch hibernation sites mid-winter. However, most cave-dwelling bats rely on a combination of seasonal cues and their ability to sense outside weather to time their emergence. If the weather turns cold again, many will head back to their hibernacula (the shelter where they spend their dormant state) for a few days. 

Some bat species are considered true hibernators. This means they dramatically lower their body temperature during deep torpor to match the cave environment, often between 2 and 8 degrees Celsius, and shut down their immune systems to conserve energy. During this time, they can survive months without food. 

The timing of spring emergence varies by species. Northern long-eared bats tend to wake earlier, while Indiana bats may remain in hibernation for a few weeks longer. Despite these differences, within species, bats are remarkably consistent in their emergence timing. 

The threat of white-nose syndrome 

A bat guide wing damaged by WNS (Photo courtesy of Rick Reynolds, Wildlife Biologist, Virginia Department of Wildlife Resources) 

It’s the extreme adaptation of true hibernators that makes them vulnerable to diseases like white-nose syndrome. WNS is a fungal infection that thrives in cold, damp environments and has reduced populations of several hibernating bat species, including the northern long-eared bat, Indiana bat and tricolored bat, by more than 90 percent.  

While the little brown bat is showing signs of slow recovery, the disease continues to impact survival and reproduction. Researchers from Virginia Tech, Radford University and the Virginia Department of Wildlife Resources are studying why some bats are more resilient, including possible changes in hibernation behavior or increased resistance. 

Migratory bat species and those that experience only brief torpor are less susceptible to WNS because their immune systems remain active. 

The bats of Virginia State Parks 

Eastern small-footed bat at Grayson Highlands State Park 

Research conducted at Virginia State Parks has revealed insights into the lives of bats across the commonwealth. Through a combination of acoustic monitoring and mist-netting, researchers have been able to better understand bat species distribution, habitat preferences and migratory patterns. 

One of the most remarkable discoveries comes from Sky Meadows State Park, which is home to one of the few remaining maternity colonies of little brown bats in Virginia. This colony has been instrumental in research focused on bat health, reproduction and population genetics.

Meanwhile, at Hungry Mother State Park, the presence of gray bats has shed light on their seasonal movements along the Holston River. Researchers have observed how these bats use different caves at various points in the summer and how they appear to be expanding their range from the Tennessee Valley into the New River watershed. This shift may be linked to the decline of little brown bats in the region due to WNS, allowing gray bats to take advantage of new foraging opportunities. 

Using radio tags and permanent towers, researchers have also documented the impressive distances gray bats travel during nightly foraging and cave-switching, sometimes covering many kilometers, even reaching areas south of Bristol. These findings highlight the dynamic nature of bat behavior and the importance of preserving diverse habitats across the state. 

A key focus of ongoing research at Sky Meadows involves studying detection probability, essentially, determining how long acoustic detectors or mist-netting must be deployed to confirm the presence of little brown bats.  

Since researchers know the bats are there, this study helps refine monitoring techniques and guidelines for agencies like the U.S. Fish and Wildlife Service. It’s a critical step in protecting species that were once common but are now increasingly rare, and it's a project the Virginia Tech research team takes great pride in. 

As for the most encountered bat species at Virginia State Parks, it varies depending on the park and the method of observation. However, statewide, the big brown bat and eastern red bat are among the most frequently recorded. 

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Indiana bat (Photo courtesy of Rick Reynolds, Wildlife Biologist, Virginia Department of Wildlife Resources)

How can you help protect bats? 

As bats emerge from hibernation or return home to begin their active season, here are a few ways you can support their survival: 

• Avoid disturbing hibernation sites like caves, mines, culverts, basements and attics, especially if bats are still present. Bats can arouse from hibernation if disturbed, which depletes the 1 to 2 grams of fat they rely on to get through the winter.   
• Protect roosting habitats by preserving forested areas and minimizing pesticide use. 
• Support clean water initiatives, as healthy aquatic ecosystems provide vital insect prey for bats. 
• Consider building a bat house. In Virginia, big brown bats are the most likely to use bat houses, especially if placed correctly. Other species, like little brown bats and occasionally northern long-eared bats, may also use bat boxes, especially where natural roosts are limited. 
  • Placement matters: In the mountains, east or west-facing bat houses work best, while on the coast, north-facing ones are often ideal. South-facing houses tend to get too hot in most parts of Virginia. The best design is a “rocket box,” a four-sided structure mounted on a central post. This lets bats move around to find the most comfortable temperature and airflow throughout the day. 

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Learning about bats at Virginia State Parks 

Starting in spring, you can find ranger-led educational programs on bats across the state, from bat wagon rides to guided night hikes. 

You can also learn more during Bat Week, an international celebration designed to raise awareness about the need for bat conservation. It will be held Oct. 24-Oct. 31. 

To find a program near you, go to www.virginiastateparks.gov/events.