Bats and Woodrats on the White Rocks: A Survey Before Climbing at Cumberland Gap

The White Rocks at Cumberland Gap National Historical Park have been a landmark for travelers throughout history. A popular trail takes hikers and riders to the top and beyond, and there is a backcountry campsite nearby. In recent years the park has been asked to open the cliffs to climbing. Before deciding, managers needed to know what climbing might do to the area's natural and cultural resources — including whether at-risk wildlife lived on the cliffs.

White Rocks, Cumberland Gap National Historical Park. NPS/Scott Teodorski.

So the NPS Inventory Program funded a survey for two at-risk species — those listed under the Endangered Species Act or of special management concern because they are rare, declining, sensitive or unique: the Allegheny woodrat (Neotoma magister) and the eastern small-footed bat (Myotis leibii).

Why bats and rats matter

Both are often misunderstood, and both are essential to their ecosystems. Cave bats bring in nutrients that support cave-dwelling fish, salamanders and other animals; nectar-eating bats pollinate agave, giant cacti and other plants; insect-eating bats like the small-footed bat can eat their own weight in insects each night. Across the United States, millions of insect-eating bats consume tons of insects nightly, leaving fewer mosquitoes to spread disease and fewer crop pests. Woodrats are important food for great horned owls, bobcats and many other animals, and they spread seeds and build "houses" that other animals use for shelter.

The two species

Allegheny woodrats, also called packrats, may look a little like the common Norway rat (Rattus norvegicus) but are native to North America and quite different. Mostly solitary, with long whiskers and hairy tails, they live in rocky woodlands of eastern North America from southern Canada to Alabama and Georgia. Their numbers have fallen across much of that range, and they have disappeared from parts of many states, including Connecticut, Massachusetts, New York, Pennsylvania, New Jersey and Maryland. They are a species of concern and closely monitored.

An Allegheny woodrat and its young. Photo by Alan Cressler, CC BY-SA 2.0.

Eastern small-footed bats are tiny — about 3 inches long — and little is known about their habits. They live across the eastern United States and southern Canada but are considered uncommon or rare because of their patchy distribution and low numbers. Kentucky lists them as threatened; human disturbance is a potential threat at more than half of the known sites where they hibernate, along with habitat loss and climate change. They roost by day and hunt insects by echolocation at night, even in dense forest like that at the foot of White Rocks, and are thought to use many roosts in a small area — hibernating in winter and sheltering in crevices and fissures in summer.

An eastern small-footed bat, carrying a tracking tag, in a crevice at Shenandoah National Park. NPS/Jonathan Fiely.

Habitat on the cliffs

White Rocks' cliffs and forests are ideal for both: each prefers rocky ledges, outcrops and cracks surrounded by forest. They use them differently. The bats roost there mostly in summer and favor deep, tight crevices they can reach from the air; the woodrats stay all year and need wider fissures for nests and food caches.

White Rocks from the air — prime habitat for both species. NPS photo.

The search

The survey ran in late summer and early fall 2021 and concentrated on parts of the cliff that might be considered for climbing routes. Both animals are active at night and hide in cracks by day, so they are hard to find.

1. Looking. Researchers rappelled down the cliff at eight sites, checking each crack for bat roosts and for woodrat nests, latrines and food caches. They found nothing.

Searching a narrow crevice for small-footed bats. NPS/Wildlife Specialists.

2. Listening. Acoustic detectors at the top and along the base of the cliff recorded the ultrasonic calls of passing bats, and software sorted them by species.

Bats leave their roosts to feed at night, where an acoustic recorder picks up their calls. Adapted from an illustration by NPS/Jen Strona.

3. Watching. Baited infrared camera traps were placed in crevices and under overhangs at the base and rim.

What they found

Both species were there. Woodrats came to the cameras every night — on the first night only 40% of the cameras caught one, but visits grew night by night. Plenty of other animals liked the peanut-butter suet bait too: mice, shrews, opossums, chipmunks, raccoons, flying squirrels and bears. No woodrat nests, latrines or caches were found, but the animals clearly lived nearby; the cameras could not tell how many.

An Allegheny woodrat caught on camera at White Rocks. NPS/Wildlife Specialists.

The detectors recorded thousands of bat calls. Fewer than 1% were small-footed bats — software identified 371 of their calls — and after full analysis the species was confirmed at 12 acoustic stations, mostly at the base of the cliff.

What it means for climbing

Finding both species shows the park has good habitat for them — encouraging — and calls for careful review of any change in how White Rocks is used. Little research exists on climbing's effects on bats and woodrats, but it could harm them: scrubbing possible roosts for holds, wear on the cliff face from ropes and chalk, clearing vegetation, and the noise and presence of people could all add stress. Without known roost or nest sites to protect, the best safeguard is to limit contact between people and these species. The results apply only to the areas surveyed.

Park managers are required by law to protect at-risk species. If climbing is allowed, measures could include:

• more research on where the woodrats and bats live and how they use the cliffs;
• seasonal or permanent climbing restrictions at sensitive places and times for roosting and raising young;
• limits on practices that damage the cliff, such as scrubbing holds or removing vegetation;
• signs to help climbers reduce their effects on bats and woodrats.

The park now has its own acoustic detectors and trail cameras for continued monitoring.

Sources

• National Park Service, Cumberland Gap National Historical Park: "Bats and Rats at Cumberland Gap: Inventories Inform Management Decisions," citing the U.S. Fish and Wildlife Service (2013), the Kentucky Department of Fish and Wildlife Resources (2023) and National Park Service (2021).