O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
135 
or other unknown effects. Reported maximum longevities for two male and two females banded in 
Ontario were six to nine years (males) and six to 12 years (females; Hitchcock, 1965). 
Mortality Factors: Historically reported mortality factors include commercialization of caves 
used as hibemacula, scientific collecting (including for rabies research), and banding (Hitchcock, 
1965). Mercury concentrations in tissue of seven eastern small-footed myotis from the northeast¬ 
ern United States were similar to those of other species of myotis, big brown bats, and tri-colored 
bats (Perimyotis subflavus), in being higher than in migratory tree bats of the genus Lasiurus (Yates 
et al., 2014). The non-migratory species considered collectively showed age, sex, and site effects 
for mercury concentrations in blood and hair, and correlations were seen between methyl mercury 
and total mercury in blood and hair of this group of species; impacts of mercury exposure on mor¬ 
tality in the sampled populations were unknown, but it was speculated that transfer in breast milk 
might have a negative effect (Yates et al., 2014). Organochlorine compounds were analyzed in tis¬ 
sues of two individuals, but with no link to mortality (Kannan et al., 2010). 
Two eastern small-footed myotis were reported crushed behind a sliding shed door in Ontario 
(Hitchcock, 1955). This species very seldom is reported dead at wind turbines (for example, Arnett 
et al., 2008; see also O’Shea et al. 2016a), although two deaths at turbines have been reported in 
Ontario (Jacques Whitford Stantech Ltd, 2009). Rabies occurs in this species (Constantine, 1979). 
However, they are seldom found or identified in public health samples taken for rabies diagnostic 
tests, perhaps because of their rarity or their infrequent use of buildings as roosts. For example, 
Whitaker and Douglas (2006) reported rabies prevalence statistics for 8,262 rabid and non-rabid 
bats taken over a 38-year period in Indiana, and no eastern small-footed myotis were among the 
carcasses examined. Similarly, only 32 individuals were found among 30,709 identified bats exam¬ 
ined for rabies in the entire United States during 1993-2000 (Mondul et al., 2003). 
DNA from the fungus causing white-nose syndrome as well as associated lesions have been 
reported for the eastern small-footed myotis (Foley et al., 2011), and a summary of changes in 
counts at 42 caves used as hibemacula showed a drop of 12% (1,303 to 1,142 bats) after the advent 
of the epizootic, the least reduction of the six species monitored at these sites (Turner et al., 2011). 
Few have been included in diagnostic reports of multiple mortality events due to white-nose syn¬ 
drome (for example, see compilations by O’Shea et al., 2016a). However, mist-netting and acoustic 
surveys in some areas suggest drops in abundance subsequent to arrival of the epizootic (Francl et 
al., 2012; Moosman et al., 2013; Coleman et al., 2014; see “Population Trend” below). Lacki et 
al. (2015) hypothesized that because these bats are small and have lower fat reserves upon enter¬ 
ing hibernation, they may be more subject to loss of energy reserves subsequent to infection by the 
fungus. 
Population Trend: Trombulak et al. (2001) assessed winter counts of all species of hibernat¬ 
ing bats at 23 caves and mines used as hibemacula in Vermont, including surveys that began dur¬ 
ing the 1930s. The eastern small-footed myotis was seldom present at most hibemacula during 
most surveys, and when present was always at low numbers, such that no conclusions could be 
drawn about changing status over time (Trombulak et al., 2001). Ellison et al. (2003) analyzed 
trends in counts for this species at ten hibemacula in Pennsylvania, with counts made in five to 12 
winters at each site (data provided by J. Hart of the Pennsylvania Game Commission). No trend 
was detected at eight sites, and two sites showed an increasing trend; overall, numbers counted 
were low, ranging from 0 to 46 bats (Ellison et al., 2003). Changes in counts at five hibemacula 
prior to the white-nose syndrome epizootic indicated positive population growth at four sites, neg¬ 
ative at 1, but 95% confidence intervals for trend estimates for this species at all hibemacula 
included negative growth (Langwig et al., 2012). Sex ratios of bats at winter hibemacula are about 
1:1 (Mohr, 1936, 1942; Hitchcock, 1949, 1965; Fenton, 1972). 
