Bk. Clark et al., SEASONAL-VARIATION IN USE OF CAVES BY THE ENDANGERED OZARK BIG-EARED BAT (CORYNORHINUS-TOWNSENDII-INGENS) IN OKLAHOMA, The American midland naturalist, 137(2), 1997, pp. 388-392
We searched 19 caves, including known maternity roosts and hibernacula
, in Adair and Delaware counties, Oklahoma, for the federally endanger
ed Ozark big-eared bat (Corynorhinus townsendii ingens) on eight occas
ions in 1989 and 1990. The same caves, and usually the same roost site
s within caves, were used during summers as maternity roosts and durin
g winters as hibernacula. An additional cave was used by large numbers
of big-eared bats (>120 individuals) during spring and autumn of both
years; this cave may serve as a transient roost and swarming site. At
least one Ozark big-eared bat was found in 17 of 19 caves during one
of the eight surveys; none was found in two caves during any survey. N
umbers of bats using hibernacula varied markedly among November, Decem
ber and February surveys, and we infer that Ozark big-eared bats were
active during winter. Because big-eared bats move among hibernacula, a
ccurate estimates of winter populations based on a single survey may n
ot be possible.