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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
species of bats, and as a consequence pre-weaning mortality (sometimes from falling into water 
beneath roosts) is high at 11.8% and is most severe shortly after birth, with multiple carcasses of 
immature bats observed under roosts (Foster et al., 1978; Hermanson and Wilkins, 1986). Adult 
mortality may also be high where prolonged hibernation does not occur because of greater expo¬ 
sure to various risks during the course of being active a large number of days of the year; twinning 
with altricial young may have been selected for as a natural demographic compensation for higher 
mortality (Foster et al., 1978; Humphrey and Gore, 1992). 
Records on predation of adults and young by snakes, owls, and opossums (Didelphis virgini- 
anus) have been summarized by Jones and Manning (1989), Humphrey and Gore (1992), and 
Lacki and Bayless (2013). Rice (1957) found 42 carcass remains taken by unspecified owls at the 
mouth of one cave and also suggested that cockroaches are important predators on fallen non¬ 
volant young. Foster et al. (1978) found two yellow rat snakes (Pantherophis alleghaniensis ) 
beneath a colony in a house with combined remains of 11 southeastern myotis (including adults) 
in their digestive tracts. 
DNA from the fungus causing white-nose syndrome was reported for the southeastern myotis 
since the early years of the epizootic (Foley et al., 2011). Clinical disease was confirmed in an indi¬ 
vidual southeastern myotis sampled in Alabama during the winter of 2016/2017 (Alabama Depart¬ 
ment of Conservation and Natural Resources, 2017), but major mortality from this disease has not 
yet been reported in this species. Fatal rabies infections occur in this species (for example, Richard¬ 
son et al., 1966; Bigler et al., 1975; Constantine, 1979; Streicker et al., 2010), but the prevalence 
can be low: one rabies-positive bat was found out of 1,998 southeastern myotis shot in flight in 
Florida during the 1950s (Schneider et al., 1957). These bats are usually infected with a rabies virus 
variant that is species-specific (Streicker et al., 2010). No mortality has been associated with 
macroparasites (species listed in Rice, 1957; Whitaker and Wilson, 1974; Jones and Manning, 
1989). 
Flooding can cause catastrophic mortality in southeastern myotis. Carcasses of at least 6,500 
of these bats were observed awash in one Florida cave in 1989 following flooding from a summer 
downpour, and an estimated 57,000 were killed in a second cave flooded by the Apalachicola River 
during record high water in 1990 (Gore and Hovis, 1994). Flooding in 1994 killed 85,000 bats in 
Snead’s Cave, Florida (Whitaker and Hamilton, 1998). Entrapment of colonies in hollow trees dur¬ 
ing flooding of bottomland hardwood forests has been observed over the short term (Rice, 2009), 
and because these bats seem to prefer hollow trees with no upper openings (see “Roosting habits” 
above), extended submergence of basal openings may also cause mortality. 
Encroachment of human populations in areas where southeastern myotis aggregate in caves 
has resulted in mortality due to vandalism and deliberate destruction (see “Management Practices 
and Concerns” below). The only detailed study on contaminants in this species focused on toxic 
elements near an industrial source in northern Florida; concentrations of cadmium were higher in 
kidneys and livers but not at levels indicative of mortality (Clark et al., 1986). 
Population Trend: Ellison et al. (2003) compiled data from six colonies across the range that 
had time series of counts on at least four separate years. Five showed no consistent trend and one 
declined based on non-parametric analyses: the maternity colony at Sweet Gum Cave in Florida 
dropped from 64,000 adults (listed in Ellison et al., 2003 as containing 170,000 bats, but that value 
included young) in 1936 to zero in 1991. Some of this decline was attributed to a cave passage 
being blocked by rock collapse and modifications to the cave entrance by the land owner (Rice, 
1957; Gore and Hovis, 1994). Anecdotal accounts and historical appraisals of status, however, also 
generally indicate declines. Barbour and Davis (1969) suggested that the population in the lower 
Ohio River Valley was rare compared to the past and possibly close to extinction; the species is 
