O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
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and lactating females moving the shortest distances. Counts of emerging bats in the Kentucky study 
ranged from one to 96 (mean 18.3) bats at female roosts, and one to 13 (mean 2.9) at male roosts 
(Johnson et al., 2012a). In southwestern Kentucky, 59 of 64 diurnal roosts found in summer 
(through radio tracking of 49 bats captured while foraging) were in hollow trees in low-lying wet¬ 
lands (Johnson and Lacki, 2013a). Bats in Kentucky used torpor in the summer, with the degree of 
torpor in females varying by stage of reproduction (Johnson and Lacki, 2013b,c). Network analy¬ 
sis of the radio-tracked bats in Kentucky (Johnson et al., 2012a) provided details of their fission- 
fusion social structure, a social system that appears to be common among species of bats that form 
colonies in trees in North America (for example, Kurta, 2005; Patriquin et al., 2010; Willis and 
Brigham, 2004). 
Louisiana : At D’Arbonne National Wildlife Refuge 44 known roost trees were all in cavities 
of hollow water tupelo trees with triangular basal openings (Gooding and Langford, 2004). Num¬ 
bers of bats using these trees varied greatly from day to day, with one to 80 bats observed when 
present; one radio-tagged female moved among at least four roost trees during a 14-day period 
(Gooding and Langford, 2004). In bottomland hardwood forests at Upper Ouachita National 
Wildlife Refuge in northeastern Louisiana, group size ranged from solitary individuals to colonies 
of up to 150, with day-to-day variability in colony sizes (Rice, 2009). Repeated searches of 57 hol¬ 
low trees along a stretch of the Ouachita River, conducted mostly in warm months, found that 32 
water tupelo (the most predominant trees) and two bald cypress were used by Rafmesque’s big- 
eared bats. Much variability occurred among roost trees in their frequency of use, with bats found 
most often in trees with higher internal cavities (Rice, 2009). 
Mississippi : Radio-tracking studies in southeastern Mississippi revealed that Rafmesque’s big- 
eared bats favored roost trees of the genus Nyssa (Trousdale and Beckett, 2005). All the roosts in 
trees found in the southeastern Mississippi study were in bottomland hardwood habitat. Openings 
to cavities used as roosts averaged 5.2 meters in height, and trees averaged 18.5 meters in height 
with an average diameter at breast height of 79 centimeters; canopy closure was high (greater than 
90%) at roost trees and surrounding 0.1-hectare plots (Trousdale and Beckett, 2005). 
South Carolina : In the largest old growth bottomland hardwood forest remaining in the U.S., 
43 roosts of Rafmesque’s big-eared bats were located by visual searches and radio tracking of 15 
individuals (Lucas et al., 2015). In this study, conducted in the Congaree National Forest on the 
South Carolina Coastal Plain, bats roosted in large-diameter hollow trees in areas with high densi¬ 
ties of hollow trees, with most using live-damaged trees in semi-permanently flooded and season¬ 
ally flooded habitat (Lucas et al., 2015). Females in maternity colonies (ranging in size from about 
6 to 100 bats, average ca. 40) switched roosts more often (every 1.3 days) than solitary males 
(every 3.8 days), moved shorter distances, and roosted more often in trees with upper openings than 
did solitary bats, suggesting that predator avoidance may be an important factor influencing the 
types of trees that reproductive females use and how often they move among roost trees (Lucas et 
al., 2015). 
Transect surveys during warm months at three study areas with appropriate habitat but differ¬ 
ing land use histories (such as habitat disturbance by logging or hot water effluents) in South Car¬ 
olina yielded 361 trees with basal cavities; 67 of these (19%) had roosting Rafmesque’s big-eared 
bats, including three maternity colonies of 20-35 bats each (Loeb, 2017). Trees with roosts had 
larger mean diameters and cavity volumes than unused trees, and were in stands with greater tree 
densities, as well as higher densities and proportions of larger trees than stands with unused trees 
(Loeb, 2017). Species and cavity types of roost trees varied among study areas along with meas¬ 
ures of roost niche breadth: the area with greatest habitat disturbance had broadest niches as 
defined by several variables except cavity volumes, whereas roost trees at the least disturbed site 
