I carefully removed the big brown bat (Eptesicus fuscus) from a mist net set over a creek and worked with a field assistant to record data. Before releasing the bat, I showed it to my field crew. Although this sounds like a typical day in the field for a bat biologist, it was far from it. On this night, the data recorder was my wife, and my daughters (ages 12 and 8) were part of my crew, which also included a graduate student from Illinois, a high school teacher from South Carolina and a wildlife biologist from Georgia. A dozen other, equally eclectic teams were also out with mist nets that night. Altogether, more than 100 bat biologists, students and others were capturing and recording bats in the Cherokee National Forest in Tennessee and the Pisgah National Forest in North Carolina. Welcome to the sixth annual Bat Blitz, sponsored by the Southeastern Bat Diversity Network. Bat Blitzes are volunteer-based surveys that provide land-management agencies with a wealth of information on bat communities at minimal cost. The idea is to conduct a “rapid biological inventory,” collecting a large volume of data in a short time by strategically scattering multiple teams across a targeted area for three days of intensive effort. Each team is led by a bat biologist with the experience, skills and equipment needed for surveying bats with mist nets.
The three days of a Bat Blitz will yield as much data as a single biologist could collect in an entire season of fieldwork. And because the work is done by volunteers, the cost to the host agency is minimal. Over the course of six blitzes, we have surveyed 175 sites across five southeastern states. If undertaken by contract biologists, the cost of those surveys would have totaled more than $260,000. Data from the 2003 Bat Blitz show that the Forest Service spent about $6,000 on food, lodging, and supplies for volunteers who put in 1,308 hours of field work, valued at more than $47,000.
In addition to providing information that helps land managers better understand and conserve local bat communities, Bat Blitzes provide excellent learning and networking opportunities for established and aspiring bat biologists, students and volunteer conservationists.
Participants in southeastern Bat Blitzes have come from more than 20 states and dozens of federal and state agencies, private corporations, universities and organizations. Non-biologists get a hands-on education about bats and research and gain a deeper appreciation for these fascinating animals. We have conducted public-education events at several blitzes, and local media attention is frequent and positive.
The Bat Blitzes are attracting more participants every year, suggesting some very encouraging trends. We are clearly seeing a growing interest in bats among land-management agencies and biologists in the southeastern U.S., and the importance of bats in maintaining healthy forests and ecosystems is being recognized increasingly by a variety of organizations and individuals. This bodes well for the future of bat research and conservation.
DARREN MILLER manages Weyerhaeuser Company’s Southern Environmental Research Program and is based in Columbus, Mississippi. He is President-Elect of the Southeastern Bat Diversity Network (SBDN) and President of the Southeastern Section of The Wildlife Society. He thanks Joy O’Keefe (Clemson University) and Tim Carter (Ball State University) for helping with this article and all the SBDN members, Blitz hosts and volunteers who have made the Bat Blitzes a success story.
Bat houses for Norway
In Norway, several bat species roost in homes and other buildings, and homeowner complaints periodically find their way into the news media. Although often based mostly on unnecessary fears and a lack of knowledge, these complaints nonetheless produce bad publicity for bats. Local officials usually advise building owners to wait until late autumn, then refurbish the roof or other access points to prevent bats from returning. That can be good advice, but it can also be expensive. And it leaves the bats in need of a new roost, which can simply transfer the problem to neighbors.
Tore Christian Michaelsen and Karl Johan Grimstad of the Norwegian Zoological Society set out to find a solution. With a grant from BCI’s Global Grassroots Conservation Fund, they initiated the first project using large-size bat houses in Norway. Most bat houses in the region have been very small compared to the typical bat house recommended by BCI for use in North America.
Michaelsen and Grimstad wanted to investigate whether the large bat boxes could be an alternative to refurbishing buildings to exclude bats and to document which bat species would use such boxes. They used Bat Conservation International’s bat-house plans, but with several modifications to meet local conditions. Because some bat species expected to use the bat houses are quite small, they limited roosting chambers to no more than three-quarters of an inch (1.9 centimeters) wide, with some as small as two-thirds of an inch (1.6 centimeters).
The bat boxes have two or three chambers and passages that allow the bats to move between them without leaving the house. Michaelsen and Grimstad considered the problem of overheating in their northern climate to be insignificant, so they did not include air vents.
Of the eight bat houses installed during the first year, seven were occupied by bats. One housed a large colony of more than 40 northern bats (Eptesicus nilssonii). Only 10 bats continued to use the building on which the bat box was situated. No attempts were made to exclude the bats from this building – they just preferred the bat house.v The rest of the bat houses contained only small numbers of soprano pipistrelles (Pipistrellus pygmaeus) when the researchers visited them, but guano deposits beneath two of them indicated they had been used at some point by many bats.
The northern bat is the largest bat that commonly uses buildings as maternity roosts in Norway and these results show that the roosting space between bat-house partitions should be no more than three-quarters of an inch.
Michaelsen and Grimstad report that the results of their pilot study point strongly toward the increased use of large bat houses in Norway and help ensure enough funding to continue their research.