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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
Each of two adult females captured over water near Flagstaff, Arizona in summer 1959 were lac- 
tating (Findley and Jones, 1961), all of 27 adult females captured over water in northern Arizona 
ponderosa pine forests in 2006 and 2007 were reproductive (including two that were post-lactat- 
ing; Solvesky and Chambers, 2009), and 22 of 25 (88%) captured over water in similar habitat in 
the same region were reproductive in 1993-1995 (Morrell et al., 1999). All of 13 females captured 
over water at three locations in New Mexico during summer 1960 were reproductive (Jones, 1961), 
as were 24 of 25 females (96%) taken over water in the Mogollon Mountains of southwestern New 
Mexico and adjacent Arizona during June and July 1960 to 1963 (C. Jones, 1964). Six of 6 females 
(100%) captured over water in Catron County, New Mexico during 1966 were reproductive (Bar¬ 
bour and Davis, 1969). Two of three adult females (67%) captured over water in southern Utah 
were reproductive (Siders and Jolly, 2009). The proportion reproductive for the cumulative total 
females taken over water over all U.S. locations and years was 95% (96 of 101 bats). 
We are unaware of any published literature with quantitative data concerning other demo¬ 
graphic aspects of female reproduction, such as age at first reproduction and inter-birth intervals. 
Survival: We are unaware of any published literature with quantitative data on survival for 
this species. 
Mortality Factors: Little is known about mortality factors affecting this species. A maternity 
colony of about 25 Allen’s big-eared bats was apparently killed when vandals set fires within the 
mine tunnel they occupied in northwestern Arizona (Cockrum and Musgrove, 1964a). Very few 
have been tested for rabies infection, with none reported positive in the literature thus far (Con¬ 
stantine, 1979, 1988; Mondul et al., 2003; Blanton et al., 2007). 
Population Trend: Seven sites that had historical records of Allen’s big-eared bats in south¬ 
western New Mexico were revisited during 2006, and all had evidence of continued presence of 
this species based on mist net captures or vocalizations (Geluso, 2006). 
Management Practices and Concerns. — In studies of several species of bats (including 
Allen’s big-eared bat) roosting under loose bark or in lightning-caused cracks in ponderosa pine 
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, thin stands of small trees to allow faster development of larger trees, and kill live large 
trees in areas of low snag density to hasten roost development. Prescribed fire but with protection 
of existing snags also may help promote development of future snags (Rabe et al., 1998a). 
Solvesky and Chambers (2009) made recommendations more specific to this species. They also 
recommended thinning dense stands of ponderosa pine using uneven-aged management and retain¬ 
ing patches of tall large-diameter trees that are allowed to mature and become standing snags, and 
removing ground fuels from areas surrounding large snags prior to using prescribed fire (Solvesky 
and Chambers, 2009). 
Allen’s big-eared bats will use artificial roosts constructed to mimic exfoliating bark on snags 
in ponderosa pine forests (Chambers et al., 2002). Scent-detection dogs have been used to locate 
roost trees used by these bats (Chambers et al., 2015). 
Macrotus californicus — California leaf-nosed bat (Family Phyllostomidae) 
Conservation Status. — National and International Designations: U.S. Fish and Wildlife 
Service (1994, 1996a,b): Species of Concern (inactive, former Category 2 candidate for listing 
under the U.S. Endangered Species Act). Bureau of Land Management (2010a, 2011b, 2017): Sen¬ 
sitive Species (Arizona, California, and Nevada state offices). U.S. Forest Service (2005a,b): Sen¬ 
sitive Species. International Union for the Conservation of Nature (2017): Least Concern. Nature- 
Serve (2017): Rounded Global Status G3, Vulnerable. 
