Bats Bats capture imagination, curiosity of Washington scientists
Posted April 2001

Summary
The study of bats in Washington state is not as developed as the science around other animals because of the difficulty of capturing the small, silent, nocturnal animals. Scientists from the Washington Department of Fish and Wildlife (WDFW) and non-profit bat conservation groups are working to piece together a puzzle that will tell which of Washington's 15 species occur where in the state. Studying bats is challenging; radio telemetry or light tagging have inherent problems, since bats in non-arid regions roost underground or inside caves and trees. And banding is potentially harmful to the bats. Discovery last year of a maternal colony of Townsend's big-eared bats by an eastern Washington WDFW biologist will enable scientists to conduct further studies. Meanwhile, funding is being sought to enable researchers to collect tissue samples on a coastal species called Keen's myotis, so the species range may be established.

By Eric Larsen, Wildlife Biologist
WDFW Habitat Program

Thus begins a process by which, on this night alone, nearly 100 bats of 12 species will be captured, identified, measured, appreciated, and finally, released back into the night from which they came. From simple "old-fashioned" survey methods like this one, biologists are able to slowly put together the pieces of a puzzle that, when completed, will tell which bats occur where on the Washington landscape.

Fifteen bat species inhabit Washington and comprise a group of animals that is not well understood. Many people think of bats as rodent-like animals that tend to get caught in one's hair, but this couldn't be farther from the truth. In fact, bats are more closely related to humans than to rodents! As for hair, no self-respecting bat would want to get caught in someone's hair! There are 925 species of bats worldwide, more than 1/4 of all mammal species, inhabiting all land masses except the polar and extreme desert regions.

Pacific Northwest bats feed chiefly on insects and may play a significant role in controlling forest and crop pests. A single little brown myotis can eat up to 1,200 insects in one hour. A large colony of bats can consume literally tons of insects each night! Bats have good vision, which they augment with a sophisticated system called "echolocation" (commonly known as SONAR), to find and identify prey and to navigate in the dark. Bats echolocate by emitting very high-pitched sounds from their mouths or noses and listening for reflected echoes. Echolocation enables a bat to detect objects as small as a mosquito while flying in the dark.

Most of the bat research conducted by Washington Department of Fish and Wildlife biologists revolves around acquiring baseline information on bats and their whereabouts.

Bat science is not as developed as the science around other animals. One significant reason for this is that bats are small, nocturnal, silent, flying animals, which makes it extremely difficult to study them. In non-arid areas, capturing bats can be extremely challenging, and even if you are fortunate to capture them, they cannot be banded because it is detrimental to them. Radio telemetry or light tagging also have inherent problems, since bats in non-arid regions roost underground in cliffs, caves and trees, and things that radio transmitters don't transmit through. Because of this, the understanding of bat ecology is in a very fundamental stage.

An example is a coastal species called Keen's myotis, the most range-restricted bat in North America. Scientists have not been able to determine whether it even occurs in Washington because of the difficulty of catching bats in those habitats. The Keen's myotis looks in the hand exactly like a sister species of bat. Funding is being sought now to enable researchers to collect tissue samples necessary to begin to investigate where this species exists in the state.

An important function of the agency's work with bats involves conservation of roost sites. Bats use many different habitats for roosting, but at certain times of the year their needs can be very specific. Colonial bats depend primarily on caves, mines and attics for daytime roosts. Most females give birth to one pup per year and raise it in a nursery colony with other females. Typically, these colonies are safe from predators and disturbance and warm enough for newborns to grow quickly. Most Northwest bats are small – about the size of a thumb – and can live relatively long lives – up to 30 years. Male bats and bats of species that tend not to aggregate are often found roosting in cliff faces, rock crevices, dead and dying trees and under bridges.

Since all bats in Washington are dependent on insects for food, they must either migrate south each fall to areas with winter insect populations or hibernate until spring when insects become plentiful. However, some bats on the west side of Washington may remain active even during the winter, as long as some insect prey is available. When they do hibernate, most of our bats hibernate in caves and mines, but not just any cave or mine is suitable as a winter roost, or as bat biologists calls them - hibernaculum. A very specific climate is required for a bat to become cold enough to go into torpor – a state of slowed metabolism – but to do so without freezing to death. Suitable hibernation sites may be a significant factor that limits bats across North America.

Protection of bat roost sites has become a primary conservation function of Washington bat biologists. In 1998, WDFW biologist Howard Ferguson discovered a colony of Townsend's big-eared bats in an old homestead cabin on private property near Spokane. His discovery became a conservation dilemma when Ferguson learned of the owner's intentions of converting the structure into a guest house.

"We had to move and move fast," recalls Ferguson. "This is a bat that is intolerant of disturbance and not a bat that uses bat boxes or other alternate roost structures." With barely a thousand individual animals known to occur statewide in only a handful of colonies, Ferguson realized that he needed to quickly mobilize an effort to save the colony from displacement. Working with willing landowners, bat enthusiasts and several granting entities, Ferguson put together a plan that would give the landowners an alternative roost site instead of the bats.

"We agreed provide a substitute for the bat cabin, leaving the old cabin to be used by the bats" Ferguson recalls. "This resulted in a win-win situation for all."

In addition to just agreeing to cooperate with WDFW in efforts to save this Townsend's colony, the landowner also agreed to permit biologists to install cameras and modems in the old log cabin as part of WDFW's "WildWatch Cam" project – a project providing the public an opportunity to witness the activities of wildlife in their natural settings. In this case, the public can watch the rare Townsend's big-eared bat – a first on the web.

Efforts like Ferguson's in Spokane County are the byproduct of nearly a decade of dedicated detective work by Washington biologists concerned with the plight of the Townsend's big-eared bat, notes WDFW biologist Eric Larsen. "Five years ago, we knew of about four active Townsend's maternity colonies in Washington. Since that time, we've identified nine more colonies for the species, allowing us to revise our estimation of the Washington population."

In addition to the efforts of Ferguson saving the roost site near Spokane, Bat Conservation International (BCI), the world's leading bat conservation organization, twice recognized Washington and in its role in the conservation of bats in its Year 2000 Annual Report, which goes out to 30 million members.

With spring approaching, Washington bat biologists recently gathered in Cle Elum to coordinate future research and conservation efforts and to reflect on past accomplishments. The Washington Bat Working Group, or WaBWoG for short, is another forum where the WDFW is actively working with other entities interested in bat conservation and research.

As the meeting drew to a close, the cold March wind blew outside, turning the scientists' thoughts toward summer nights, soggy tennis shoes and the many questions about Washington's bats yet unanswered.

Soon the nets will be set again in places where little is known about bats, and the first cries of "got one" will again punctuate the darkest nights of summer.

Author Biographies

Eric Larsen is a wildlife biologist who serves as coordinator of the WDFW Priority Habitats and Species Program. He was hired by the former Department of Wildlife in 1993 to develop management recommendations for some of Washington's priority habitats. The Department has identified 161 priority species and 19 priority habitats. Larsen graduated from The Evergreen State College, with a bachelor of science degree concentrating on ecology and evolution. Before joining the Department, he worked on field studies of marine mammals, shorebirds and the at-sea ecology of marbled murrelets. He also worked at the University of Washington's Burke Museum on a study of natural selection mechanisms in red-wing blackbirds.

Howard Ferguson has worked for WDFW since 1993, first doing computer database programming for the game management division in Olympia, serving as urban wildlife biologist in Spokane since 1995. He has a bachelor's degree in biology from the University of California - San Diego, a master's degree in wildlife biology from Virginia Polytechnic Institute and has almost completed a master's degree in computer science from San Diego State University.

Related research
Two projects supported jointly by WDFW, Bat Conservation International and Disney Wildlife Conservation Fund, B.E. Meyers and Timothy K. Brown:

• Study of the Townsend's big-eared bat maternity colony, studying "non-intrusive" techniques - including remote controlled cameras, VCR and remote web feed.
• Research to attempt to find the Townsend's hibernacula - where do they spend the winters?

Related Links
For further information, visit the websites of the following organizations:

The WDFW web site for the WildWatchCams is: http://wdfw.wa.gov/wildwatch/

Bat Conservation International (BCI)
PO Box 162603
Austin TX 78716
512-327-9721
http://www.batcon.org

BCI is a nonprofit organization dedicated to the conservation of bats, and education of the public on bat issues worldwide. They maintain extensive libraries of written materials and images. They specialize in educational material on bats and provide information on rabies, bat relocation, bat houses, and other bat-related topics.

Bats Northwest (BNW)
4742 42nd Ave. SW
Seattle WA 98116
206-256-0406
http://www.batsnorthwest.org

BNW is a nonprofit organization dedicated to the conservation of bats, and education of the public on bat issues in the Pacific Northwest. They conduct presentations to various organizations and serve as a local clearinghouse for bat related information.

Bat Conservation Efforts

Washington Bat Working Group
State-wide effort to coordinate bat education, management, and research activities. Partnership of Washington bat biologists and conservationists working jointly and exchanging ideas, information, and equipment. Founded in 1994.

Western States Bat Working Group
West-wide effort to coordinate individual state bat activities and conservation direction. Founded in 1996.

Washington Bat Conservation Strategy
Conservation plan to identify gaps in knowledge, help identify research, education, and conservation needs relative to bats in Washington. Part of the North American Bat Conservation Partnership. Launched by WDFW in 2000.

North America Bat Conservation Partnership
A planning effort across the North American continent to formulate long-term, landscape-level conservation strategies for North American bats. Organized by Bat Conservation International.

Northwest Bat Cooperative
NBC is a coop of state and federal agencies, private industry, and nonprofit organizations who collectively fund bat research specific to the Pacific Northwest. The WDFW is a coop contributor. The first NBC grant was awarded this year for a three year study on roost site selection in riparian forests of the Pacific Northwest.

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