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Virginia big-eared bat |
The Virginia big-eared bat (Corynorhinus townsendii virginianus) had a population of about 3,500 bats when it was listed as an endangered species in 1979 [9]. It increased to about 10,000 during the 1980s [2], 15,000 during the 1990s [3, 4], and was estimated at 18,442 bats after the last count in 2000 [4].
VIRGINIA Tazewell Count #2 is both a maternity and hibernacula cave. The maternity population grew from the 200s in 1991 and 1992 to an average of about 550 from 1993 to 1999. Equipment failure precluded a 2002 count, but the surveyors believed the population size to be similar to previous years. The hibernacula was estimated at 2,000 bats between 1985 and 1990 based on subjective reports by cavers. Systematic surveys began in 1993. Prior to construction of a protective gate, the population was 476 in 1993 and 525 in 1995. The post-gate population was 1,600 in 1996 and 1,160 in 1999, with the latter year considered low due to unusual warmth. Surveys were discontinued in 2001 due to safety concerns over the unstable 100+ foot drop entrance. The overall Virginia trend suggests a increase in the observed maternity population to about 950 females in the 1990s, and an increase in the hibernacula population to about 1,600 observed bats. Based these observed numbers, the state population has been estimated at about 2,200 bats [2, 3, 4]. NORTH CAROLINA KENTUCKY - The Arbogast/Cave Hollow population increased from 650 bats (1983) to 1,137 (1988) after a year-round closure was instituted and fence erected [5]. Vandals broke into the cave and built a fire near the maternity roost site between June 1988 and June 1989, reducing the population to 286 bats in 1989. The entrance was subsequently gated and the population slowly but steadily climbed to 648 in 2005 [6]. - The Lambert Cave population declined between 1999 and 200 when the large tree next to its entrance died, allowing sunlight to increase herbaceous vegetation which blocked the entrance [7]. The West Virginia Department of Natural Resources has controlled the vegetation and planted a new tree at the site, causing the population to bounce back. - The Cliff maternity site was discovered in 1992 and was the first or second largest through 2005 [6]. [1] Reynolds, R. 2005. Corynorhinus townsendii virginianus Survey Counts for Virginia. Unpublished report, Virginia Department of Game and Inland Fisheries. |
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