42 
PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
habitat zones documented the occurrence of this species throughout the region, particularly in 
juniper-covered foothills, caves, and river canyons with high cliffs in a variety of habitat types 
(Ports and Bradley, 1996). 
Southwestern U.S.: Arizona : Townsend’s big-eared bats ranked seventh in relative abun¬ 
dance (214 captures among 3,458 individuals) of 17 species netted over water in Mohave County 
in northwestern Arizona, where they were captured at sites in multiple habitat types (Cockrum et 
al., 1996). At Kofa National Wildlife Refuge in southwestern Arizona, they ranked fifth of 6 species 
documented drinking at small artificial water sources in lower Colorado River Sonoran and Ari¬ 
zona Upland Sonoran Desertscrub vegetation types, with 22 individuals captured among 427 bats 
(Rabe and Rosenstock, 2005). They were the least frequently captured bat in ponderosa pine forests 
at about 2,200 to 2,600 meters elevation on the Coconino Plateau in northern Arizona (two cap¬ 
tured among 1,673 bats of 15 species; Morrell et al., 1999). This species ranked seventh in abun¬ 
dance among 17 species of bats (46 captured of 1,171 total bats netted) taken over water mostly in 
ponderosa pine and pinon-juniper habitats of the Arizona Strip in northwestern Arizona (Herder, 
1998). They were not documented among 353 individuals of 15 species captured in ponderosa pine 
forests at 1,350 to 1,930 meters elevation along the East Verde River below the Mogollon Rim, on 
the Tonto National Forest in central Arizona (Lutch, 1996). 
New Mexico: Townsend’s big-eared bat was the least abundant species taken in mist nets in 
the Jemez Mountains in north-central New Mexico during the 1990s, where capture sites spanned 
elevations between 1,753 and 2,774 meters and ranged from pinon-juniper woodlands to spruce-fir 
forests (seven captures among 1,532 bats of 15 species), with echolocation activity detected only 
in riparian and pinon-juniper habitats (Bogan et al., 1998; Ellison et al., 2005). Also in northern 
New Mexico, these bats were not documented among 302 bats of 10-11 species netted in mostly 
ponderosa pine habitat on Mount Taylor during 2006 and 2007 (Geluso, 2008). 
Three studies assessed the relative abundance of bats at various locations in the San Mateo 
Mountains of west-central New Mexico. No Townsend’s big-eared bats were captured in netting 
over several stock ponds in ponderosa pine forest, where a total of 447 bats of seven to eight 
species were documented (Chung-MacCoubrey, 2005). One was captured among 855 individuals 
of 16-17 species captured during 1970 at Nogal Canyon, Socorro County, in habitats described as 
pinyon-juniper, pine-oak woodlands, and mixed-conifer forest (Black, 1974). The species ranked 
ninth in relative abundance (eight captured among 1,390 bats and 11 species) during 19 summers 
of netting during the period 1971-2005, at a pond in ponderosa pine/mixed pine forests at an ele¬ 
vation of 2,573 meters in Bear Trap Canyon, Socorro County (Geluso and Geluso, 2012). None 
were captured in a survey documenting six species and 130 individuals netted over water along the 
middle Rio Grande in the Bosque del Apache National Wildlife Refuge in central New Mexico 
(Chung-MacCoubrey, 1999), although an individual was taken at a roost at a building on the refuge 
(Valdez et al., 1999b). They were low in relative abundance (a total of 35 among 1,595 bats of 20 
species captured, ranking thirteenth) in the Mogollon Mountains of western New Mexico and adja¬ 
cent Arizona, where they were most often captured in woodlands and evergreen forest above 1,524 
meters (Jones, 1965). Similar relative abundance and habitats were reported in a separate analysis 
limited to three sites over water in western New Mexico and including additional years of sampling 
(Jones and Suttkus, 1972). Somewhat farther south, Jones (2016) documented bats captured dur¬ 
ing surveys of the Greater Gila region of Catron, Grant, and Sierra counties; this species ranked 
second-to-least abundant, with two taken among 282 captures of 16-17 species (Jones, 2016). A 
survey that took place at 37 sites across several habitat types in much of New Mexico in 2006 
yielded 1,752 bats of 21 species, with one Townsend’s big-eared bat captured, ranking lowest in 
relative abundance (Geluso, 2006, 2017). 
