O’SHEA, CRYAN & BOGAN: UNITED STATES BAT SPECIES OF CONCERN 
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Adult females were radio tracked to 44 roosts in ponderosa pine dominated forests in northern 
Arizona: 14 in cracks in rocks on the ground, 24 in ponderosa pine snags, four in Gambel oak cav¬ 
ities or snags, and two in downed logs (Rabe et al., 1998a). Three long-eared myotis females radio 
tracked in east-central Arizona ponderosa pine forest roosted in one ponderosa pine and two south¬ 
western white pine (Pinus strobiformis) snags, with two exit counts of 5-6 bats observed (Saun¬ 
ders, 2015). 
In pinon-juniper woodlands of the Gallinas Mountains of New Mexico, Chung-MacCoubrey 
(1996) found a maternity colony of five females roosting in a cavity in the dead trunk of a live 
juniper. Lactating females radio tagged in late July and early August did not roost in colonies but 
changed roosts daily, moving among live and dead junipers (primarily Juniperus monosperma ) and 
roosting within the twisted folds of trunks. Year-to-year reuse of roosts in trees was documented 
(Chung-MacCoubrey, 2003). 
Warm Season Roosts in Buildings: Reports of non-winter use of buildings as roosts by long¬ 
eared myotis are uncommon. Apparently solitary individuals have been reported to roost in cracks 
or among rafters of buildings on Santa Cruz and Santa Catalina islands, California (von Bloeker, 
1967). They have been observed roosting in an abandoned ranch house in Routt County, Colorado, 
and apparently night roosting in other buildings in the state (Cary, 1911; Warren, 1942). A pregnant 
female in southern Alberta roosted in a shed for two days but otherwise used natural erosion cavi¬ 
ties and channels in the ground (Nixon et al., 2009). 
Night Roosts: Long-eared myotis do not seem to use night roosts to a major degree. Howev¬ 
er, they have been reported night-roosting in an abandoned shed in northwestern South Dakota 
(Andersen and Jones, 1971), and low numbers of this species were reported to utilize bridges as 
night roosts in the proximity of the upper Sacramento River in California (Pierson et al., 1996b). 
Reproductive females studied in Alberta, Canada spent most of the night foraging, roosting for only 
a small proportion of each night (Chruszcz and Barclay, 2003). In contrast, Albright (1959) report¬ 
ed them to be the most common night roosting bat (predominantly males) at a cave at Oregon 
Caves National Monument, especially during August. 
Population Ecology. — Litter Size, Natality, and Female Reproduction: Typical litter 
size appears to be one. One female long-eared myotis taken in California had a single embryo 
(Grinnell, 1918), as did two females taken in mountains in southern Nevada (Burt, 1934; Deacon 
et al., 1964), five females from northwestern South Dakota (Jones and Genoways, 1967; Andersen 
and Jones, 1971), and a female from the Chiricahua Mountains of southeastern Arizona (Cockrum 
and Ordway, 1959). Two females with one embryo each were collected in the San Gabriel Moun¬ 
tains of southern California (Vaughan, 1954), and in southeastern Montana (Jones et al., 1973). 
Cockrum (1955) summarized records for six other females from multiple locations, each with sin¬ 
gle embryos or young. 
Natality rates of long-eared myotis are variable and can be biased by place of capture. Seven 
of seven females (100%) taken from a maternity colony in British Columbia were all pregnant 
(Munro and Cowan, 1944). Natality estimates based on captures at watering sites, foraging places, 
and flyways are lower. Reproductive rates of adult female M. evotis in southwestern Colorado var¬ 
ied with the amount of spring precipitation, averaging 34% (32 females) during the 2006 drought 
year and 69% (42 females) the following year when spring precipitation was higher and insect 
abundance showed a corresponding increase (Snider, 2009; O’Shea et al., 2011a). Four of six 
(66%) long-eared myotis taken at Mesa Verde National Park in early June 1989-1994 were preg¬ 
nant (Chung-MacCoubrey and Bogan, 2003). Two of eight adult females (25%) captured during 
summer over water in west-central Nevada were reproductive (Kuenzi et al., 1999). 
A female reproductive rate of 55% (21 of 38 bats) during summers 1987 and 1988 was found 
