Studying Bats

Bats help maintain healthy ecosystems and are important members of our communities and natural spaces, including national parks. With threats like habitat loss, wind energy turbines, and white-nose syndrome, researchers and wildlife managers spend time and resources studying bats on park lands. This information is necessary to determine the best ways to protect and manage bats in national parks and across larger landscapes. Questions that researchers or managers ask range from basics like where different species live and what habitats they use for shelter and food, to how many bats there are of different species and how that changes over time, to identifying ways in which we can help reduce the harmful effects of diseases and other threats to bats.

What do researchers want to know about bats?

Questions Researchers Ask

What species of bats and how many of each live here? How has this changed over time?

This information is the first step in science-based management of bats in parks. Species that are listed as threatened or endangered require special attention. Also, understanding how these populations have changed over time helps managers identify trends related to migration, changes in habitat or climate, and impacts of disease or other threats to bats.

Find out which bat species are present in national parks.

Where do bats roost, forage, hibernate, and raise young in the park?

Wildlife managers in parks need to know where bats live and what habitats they need for shelter and food in order to protect them. This information is used to make a variety of management decisions that may affect where bats live, like caves, forests, cliffs or talus, and sometimes even buildings and bridges in parks. It is also helpful to know where bats can be found during different times of the year in case researchers, park managers, or others need to count them or catch them for surveys, scientific studies, or surveillance for diseases, like white-nose syndrome.

Learn more in this article: Bats in Acadia: Facing Challenges but Hanging on

Are the bat populations healthy?

Monitoring the health of bats lets researchers know if the populations have white-nose syndrome or other diseases. It also lets managers know if bats suffer from other stressors, like contaminant poisoning from heavy metals or pesticides for example.

Annual survival rates and reproduction rates are indicative of a healthy population. A female bat typically only gives birth to one pup a year, so every baby bat is important and it can take a long time for bat populations to recover from a decline. Gather some of this information requires capturing bats to collect samples, determine pregnancy or identify juveniles, but valuable information can also be obtained remotely. Counting the number of bats hibernating within a cave during winter or the number of bats that emerge from a roost in summer can provide population estimates that can be repeated over many years to determine population trends. Stable or increasing populations are a sign that the population is healthy, but severe declines like those observed following arrival of WNS to North America very concerning.

Learn more about white-nose syndrome.

Researchers in Mount Rainier band bats to monitor colony health. Researchers must wear protective gear to protect both bats and humans from possibly transmitting diseases to each other.

NPS / Chestnut

Catching and Studying Bats

Bats are small animals that can be hard to find! They are often well-hidden in trees or deep inside caves and only come out at night to hunt for insects. This makes bats difficult to study, so researchers have developed special techniques for studying and counting bats. In response to the multitude of threats facing bat populations in North America, the National Park Service collaborates with other management agencies and bat conservation organizations to develop coordinated bat population monitoring efforts.

Bat Researchers in Action

See scientists use various methods for capturing and studying bats in these short videos. More videos are available on our Multimedia page.

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  Bat Study at Homestead

  This study seeks a threatened specie and more information about how bats utilize park habitat.

  Duration:

  6 minutes, 4 seconds

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  Bats: Tiny Creatures, Big Challenges

  Although bats are small mammals, they face some large challenges. Learn more about what the National Park Service is doing to preserve bat populations in national parks.

  Duration:

  10 minutes, 6 seconds

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  Outside Science (inside parks): Bats at Glen Canyon National Recreation Area

  Follow along as our crew learns about bats in Glen Canyon National Recreation Area

  Duration:

  3 minutes, 56 seconds

Four Methods for Catching and Studying Bats

Long-legged bat in mist net

USGS / P. Cryan

1. Mist nets

This long-legged bat is temporarily tangled in a mist net. This loose mesh is practically invisible when strung up between two poles at dusk, and bats get caught in it when they fly by. Park staff or researchers can then carefully free the bat and collect information, such as:

• the type of species or weight,
• collect samples for genetic studies or disease surveillance, or
• mark the bat with a band or other device so it can be tracked.

The bat is then released to continue its nightly activities. Bats are quick learners, so park staff and researchers have to be creative about where to set up the nets and typically can't catch the same bat twice.

Two researchers sit in the forest at a cave entrance and use infrared scopes to survey bats and record their observations.

NPS Photo

2. Field surveys

In a field survey, scientists visit locations where bats are likely to live—caves, trees, crevices, abandoned mines, etc. They are often looking for numbers and species of bats that are at these locations at different times of the year. Some special tools, like infrared cameras or telephoto lenses, can be helpful for finding and counting bats. Guano (or bat poop) samples collected at those locations can also be used to determine the bat species that use that roost.

Conduct your own bat survey!

The video below shows an evening departure of Mexican free-tailed bats leaving a roost in Capitol Reef National Park. This is an example of what scientists could see when they are conducting a bat survey in the field. How many bats can you count?

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  Bat Surveys

  Watch an evening departure of about 200 Mexican free-tailed bats (Tadarida brasiliensis) from a roost in Capitol Reef. Mexican free-tails are found in the western U.S., south through Mexico, Central America and into northern South America. Mexican free-tailed bats in Capitol Reef migrate south to Central America and Mexico during the winter. These insectivorous bats have dark brown or gray colored fur, they weigh 0.4-0.5 oz (11-14 g) and their wingspan is between 12-14 in (30-35 cm). They have broad, black, forward pointing ears, wrinkled lips, and their wings are long and narrow; they are very fast flyers. Although this roost only numbered about 200 bats, colonies of over 20,000,000 can be found elsewhere in their range!

  Duration:

  1 minute, 5 seconds

USGS scientist radiotracking bats at Mesa Verde National Park. The superimposed image is of a scientist attaching a radio transmitter to a bat.

USGS / P. Cryan

3. Radio transmitters

In some cases, researchers need to be able to track a bat to learn about the secret places that bats go to rest, hibernate or raise young. The information helps managers know where bats are during different times of the year and what locations they need to protect for the bats.

To do this, researchers attach temporary radio transmitters onto the back of a bat (like a tiny backpack) after it is captured using a net or other method. The bat is then released. Throughout the next few weeks, the researchers can find the bat and track its movements using an antenna to detect the signal that is constantly sent out from the tiny radiotransmitter on the bat. After a few weeks, the transmitter falls off and the bat can return to its secretive ways.

A bat researcher sets up acoustic monitoring equipment in Arches National Park.

NPS / Veronica Verdin

4. Acoustic surveys

Scientists can record the echolocations or calls that bats make when they are flying through the air using specialized microphones and recording devices. Just like birds, different species of bats tend to make different types of sounds, which allows the researcher to identify the species of bat that flew by.

The recording device may be left in the field to record bat calls over a number of nights or can be used to survey an area in one night by walking or driving along a specific route.

Additionally, many parks have permanent monitoring stations to track bat activity year-round.