Home
Field Notes
 
U.S. Fish & Wildlife Service
Field Notes Entry   
Service Sends Bat Surveyors Underground to Shed Light on on Indiana Bat Population Estimates
Midwest Region, January 27, 2006
Print Friendly Version
Biologists from six states participated in an Indiana bat winter survey exercise in the Magazine Mine, in southern Illinois. The Service sponsored the exercise, which was designed to quantify the amount of variability among population estimates generated by surveyors employing different survey techniques. 
- Photo courtesy of Al Hicks, New York State Department of Environmental Conservation
Biologists from six states participated in an Indiana bat winter survey exercise in the Magazine Mine, in southern Illinois. The Service sponsored the exercise, which was designed to quantify the amount of variability among population estimates generated by surveyors employing different survey techniques.

- Photo courtesy of Al Hicks, New York State Department of Environmental Conservation

- Photo Credit: n/a
One of 52 different clusters of hibernating Indiana bats surveyed in the mine.
- Photo courtesy of Al Hicks, New York State Department of Environmental Conservation
One of 52 different clusters of hibernating Indiana bats surveyed in the mine.

- Photo courtesy of Al Hicks, New York State Department of Environmental Conservation

- Photo Credit: n/a

An Indiana bat survey exercise was held at the abandoned Magazine Mine in the southern tip of Illinois (Alexander County) on Jan. 27, 2006, to help the Service quantify the amount of variability associated with winter population estimates made by different surveyors using different and similar techniques. 

Five survey teams from Illinois, Indiana, Kentucky, Missouri, and New York used their traditional survey techniques for estimating the number of Indiana bats within 52 designated clusters that ranged in size from tens of bats to thousands of bats.  Once the teams have finished calculating their estimates and/or have completed counting bats in their digital photographs they will be providing their data to Dr. Vicky Meretsky, an associate professor at Indiana University (and former Service biologist in Region 2) for statistical analysis. Dr. Meretsky helped design and coordinate the exercise and will be assessing the amount of variability among the five teams' estimates and techniques.  

In all, 17 people entered the mine and participated in the exercise, including biologists with the Service, U.S. Forest Service, four state agencies, three universities, an environmental consulting firm, a karst conservancy, and the private mining company.  The Service participants included Andy King from the Bloomington Field Office and Bob Currie from the Asheville, North Carolina Field Office.

In order to minimize disturbance levels, participation was limited to those teams that routinely survey hibernacula containing large clusters/numbers of Indiana bats.  The total number of people (n=17) that participated in the exercise was similar to that which is normally used to conduct the biennial survey of the Magazine Mine.  We were concerned about how the bats would respond to having many people, lights, camera flashes etc., beneath them during the exercise, but everything went very smoothly and overall disturbance levels to the bats appeared to be similar to or less than that which typically occurs during the biennial surveys.

In 2005, the hibernating population of Indiana bats in Magazine Mine was estimated to be 33,500, which is remarkable considering that this underground silica mine was not abandoned until 1980 and Indiana bats weren’t discovered there until 1999; with an initial population estimated at 9,000 bats.  The Magazine Mine is now home to Illinois' largest and most rapidly growing population of Indiana bats and other bat species.  The mine is owned and managed by the Unimin Corporation, the world’s largest producer of microcrystalline silica and a valued partner in bat conservation.  Most of the land on the surface above the mine is forested and is part of the Shawnee National Forest, but the majority of the underground mineral rights belong to Unimin.

Information from this exercise will be used to estimate variability in past surveys and to assess what level of certainty might be available from future surveys that could lead to downlisting and delisting of the Indiana bat.  Dr. Meretsky and other participants will report their findings to the Service and plan to incorporate them into a peer-reviewed publication on Indiana bat population estimates and trends.  The Bloomington Field Office intends to use the findings from this exercise to make improvements to the existing winter bat survey protocol that would further reduce variability among survey estimates and ultimately increase the Service's confidence levels in range-wide Indiana bat population estimates and trends.

The Service is especially grateful to Mr. Rick Fox with Unimin, who kindly granted access to Magazine Mine, arranged a meeting room, and hosted a most welcome dinner for all the exercise participants.  Similar gratitude was extended to Joe Kath with the Illinois DNR, Dr. Tim Carter with Southern Illinois University, and Dr. Vicky Meretsky with Indiana University for their assistance in coordinating the exercise

Questions regarding this exercise may be sent to Andy King in the Bloomington Field Office (Andrew_King@fws.gov) or to Dr. Vicky Meretsky at Indiana University (meretsky@indiana.edu).

 


Contact Info: Larry Dean, 612-713-5312, Larry_Dean@fws.gov



Send to:
From:

Notes:
Find a Field Notes Entry

Search by keyword

Search by State




Search by Region


US Fish and Wildlife Service footer