O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
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across all years, and Cormack-Jolly-Seber recapture models for open populations were applied to 
estimate abundance, apparent survival, and indirect recruitment based on three to five capture 
attempts at roosts each summer. Most (165) of the banded bats were never recaptured. Apparent 
survival estimates over the course of the study were 0.64 ± 0.17 (SD) for females and 0.45 ± 0.32 
for males (Diamond et al., 2015) and varied by sex and year. These estimates appear unsustainable 
(see review in O’Shea et al., 2011c) but possibly may include permanent emigration, banding- 
caused mortality (Hitchcock, 1965; O’Shea et al., 2004), or other unknown effects. Females were 
recaptured more often than males, indicating greater roost fidelity, with capture probabilities of 
0.63 ± 0.18 (SD). Estimated population size (all inferences presumably for the 24 one-hectare plots 
sampled) varied each year from 41 to 68 females, and 26 to 143 males. Results suggested that over¬ 
all population growth rates were flat and not increasing (Diamond et al., 2015). 
Mortality Factors: Neonatal mortality in Arizona myotis is low, estimated at about 2% for a 
colony studied in an attic near Las Vegas, New Mexico (O’Farrell and Studier, 1973). Ectopara¬ 
sites have been well documented (Valdez et al., 2009), helminths reported (Cain and Studier, 1974), 
and coronaviruses have been detected (Dominguez et al., 2007), but no mortality from these agents 
has been described. These bats are undoubtedly susceptible to rabies virus infection, but the liter¬ 
ature on rabies in bats does not distinguish M. occultus from M. lucifugus. No mortality due to 
exposure to environmental contaminants has been described, although monitoring for metals and 
radiation is planned for bats sampled at a uranium mine site in Arizona (Hinck et al., 2014). 
Population Trend: Other than occasional estimates of colony sizes and results of Diamond et 
al. (2015) given above, we found no information on population size and trend for the Arizona 
myotis (see also “Survival” above for an analysis at one study site). Pierson and Rainey (1998d) 
noted that the bridge housing the maternity colony reported by Stager (1943b) as subsequently 
demolished and replaced; the fate of that colony was unknown, and the species had not been doc¬ 
umented in California since a single record in 1969. However, 17 individuals (including reproduc¬ 
tive females) were captured on the Arizona side of the lower Colorado River on the ‘ Ahakhav Trib¬ 
al Preserve and the Cibola Valley Conservation Area about 0.5 kilometers from the California bor¬ 
der in 2007 and 2010 (Calvert and Neiswenter, 2012). 
Management Practices and Concerns. — In studies of several species of bats (including 
the Arizona myotis) roosting under loose bark or in lightning-caused cracks of snags in northern 
Arizona, Rabe et al. (1998a) recommended measures to help recruit snags with loose bark as bat 
roosts. They suggested that forest management should retain large trees that die in place, should 
thin stands of small trees to allow faster development of larger trees, and should kill live large trees 
in areas of low snag density to hasten roost development. Prescribed fire with protection of exist¬ 
ing snags also may help promote development of future snags (Rabe et al., 1998a). 
Arizona myotis will use artificial roosts constructed to mimic exfoliating bark on snags in pon- 
derosa pine forests in northern Arizona, where they also will occupy wooden bat boxes (Mering 
and Chambers, 2012; Diamond et al., 2015). The species has been captured in flight within exper¬ 
imentally restored cottonwood-willow riparian habitats along the lower Colorado River (Calvert 
and Neiswenter, 2012). 
Considering the close taxonomic relationship between Arizona myotis and little brown myotis, 
the latter of which is among the most susceptible to white-nose syndrome (Frick et al., 2010a), 
monitoring populations of Arizona myotis may help with early detection of disease arrival in south¬ 
western regions of the U.S. 
