Bat Population Monitoring in Fredericksburg and Spotsylvania National Military Park

A tri-colored bat being held by a biologist.
Tri-colored bats are listed as a Virginia state endangered species. They are relatively uncommon in Fredericksburg and Spotsylvania National Military Park.

Photo courtesy of Nick Kalen.

Why is the park interested in bats?

Bats are an important part of ecosystems and food webs. Though some species of bats feed on fruit, seeds, or pollen, the species that live in Virginia are insectivores. They consume huge numbers of insects every night, filling a unique ecosystem role as nocturnal insect predators. Unfortunately, a new disease called white-nose syndrome is affecting bats across the United States. To better protect bats, biologists are studying how local bat populations are changing.

Research Highlights

  • Recent monitoring (2016-2017) detected 11 species of bats in the park, including two federally threatened or endangered species.
  • White-nose syndrome has negatively affected several of these species.
  • Bat activity is highest near the Fredericksburg Battlefield, primarily due to high activity of urban-adapted bats (i.e. big brown bats).

How do biologists study bats? What have they learned about bats in the park?

Biologists have creative ways of studying these unique animals. Bats use echolocation to navigate and catch insect prey during the dark of night. People can’t hear these bat calls, so biologists use special microphones, called acoustic detectors, to record the sounds. By analyzing the bat calls, biologists can identify which specific bat species are present in an area during certain times of the year.

From 2016-2017, scientists used acoustic detectors to document 11 species of bats in the park (see Figure 1 below). The most commonly detected bat species was the big brown bat (Eptesicus fuscus). Interestingly, bat activity was highest in the most urbanized area of the park (Fredericksburg Battlefield). In this area, big brown bats are likely abundant. Big brown bats can easily adapt to urban areas and are less impacted by white-nose syndrome than other bats.

Researchers are also capturing bats and using radio-tracking devices to follow bats to important habitats. Park managers can then better protect these areas. For example, several species of bats prefer mature forests as feeding areas. Mature forests are rare in the Fredericksburg area, suggesting that the older forests that remain are likely serving as critical bat habitat.
Bar chart showing bat species activity based on the number of recorded bat calls in the park.
Figure 1. Activity levels of bat species recorded by acoustic detectors in Fredericksburg and Spotsylvania National Military Park, 2016-2017.
 A biologist holding a bat and examining the wing for damage from white-nose syndrome.
A biologist examines the wing of a bat for damage from white-nose syndrome.

NPS photo.

What about rare bat species?

During the summer, there are four rare bat species that can be found in the park. These include the little brown bat (Myotis lucifugus), the tri-colored bat (Perimyotis subflavus), the Indiana bat (Myotis sodalis), and the northern long-eared bat (Myotis septentrionalis). The latter two are protected by the Endangered Species Act and are not common in the park. All of these rare species are sensitive to white-nose syndrome.

These rare bats spend their summer days roosting in tree cavities and snags, under tree bark, or in buildings. At night, they emerge to feed across the park’s landscape. During the fall, these species of bats usually travel to caves or mines, where they hibernate for the winter. In these caves and mines, they can contract white-nose syndrome and die.

What is the park doing to help bats?

The data being collected on bats will help park managers conserve bats and their habitat. Protecting hollow trees and snags where bats raise their young and preserving mature hardwood forests will help reduce the impacts of the disease. White-nose syndrome remains an extraordinarily dangerous threat to bat populations—sadly, some species may ultimately disappear from the region.

For more information:

Contact Natural Resource Manager Gregg Kneipp.

Last updated: September 25, 2018