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Goal: Sustain Our Nation’s Forests and Grasslands Scientists expand knowledge on bats: Silviculture effects, warm winters, and identification

A federally threatened northern long-eared bat captured during netting for bats. (Forest Service photo by Phillip N. Jordan)


Bats are one of the most threatened groups of mammals worldwide. SRS researchers are studying bats and developing conservation strategies that land managers can use. For example, a recent literature synthesis identifies silvicultural treatments compatible to bat conservation.

Results from another bat study will make it easier to identify two look-alike bat species: Gray bats (Myotis grisescens) and Southeastern bats (Myotis austroriparius).

Researchers also estimated the survival rates of tricolored bats as they hibernated over the winter in small abandoned mines on the Ouachita National Forest. Survival rates varied greatly, but the results suggest that winters in the South can be warm enough that some insects are still active, allowing bats to replace energy stores—even if white-nose syndrome rouses them from hibernation.


White-nose syndrome has killed millions of bats. Tricolored bats have declined so much that the U.S. Fish and Wildlife Service is considering listing them as an endangered species, which would have huge management implications for national forests.

For five years, SRS researchers monitored tricolored bats hibernating in small abandoned mines of the Ouachita National Forest and estimated their survival rate. In some mines, bats left during the winter and new bats entered, which suggests they leave the mines and forage during the winter. The study suggests that bats in small mines in more southerly areas may not be affected as greatly by white-nose syndrome as bats in caves and mines of the upper Midwest and northeastern U.S.

In the field, wildlife biologists and researchers can now easily distinguish between gray bats (Myotis grisescens) and Southeastern bats (Myotis austroriparius). A notch in the claws of the feet and the length of the forearm are the two best characteristics for distinguishing these species, according to the research by SRS scientists and partners.

Active management practices such as thinning and prescribed fire do not harm—and often improve—foraging and roosting habitat for bats, according to a recent SRS synthesis study. The study focuses on how silvicultural treatments affect roosting and foraging in temperate-zone bats. The study synthesizes 88 studies on over 70 insect-eating bat species from North America, Europe, Australia, and New Zealand. Landscape planning to assure a diversity of stand ages—from recently cut to mature—will provide for the roosting and foraging needs of insect-eating bats in temperate areas.

Warm winters and tricolored bats

Principal Investigator
Roger W. Perry, Research Wildlife Biologist
4159 - Southern Pine Ecology and Management
Strategic Program Area
Wildlife and Fish
Survival and persistence of tricolored bats hibernating in Arkansas mines
CompassLive Article
Bat Survival in Arkansas Mines
Research Partner
Ouachita National Forest

Silviculture effects on bats

Principal Investigator
Susan C. Loeb, Research Ecologist
4157 - Upland Hardwood Ecology and Management
Strategic Program Area
Wildlife and Fish