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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
tive female western small-footed myotis outnumbered reproductive females in ponderosa pine 
dominated habitats in western South Dakota, with reproductive females taken at lower mean ele¬ 
vations (Cryan et al., 2000); 171 of 198 (86%) captured at nine sites in Badlands National Park, 
South Dakota were males (Bogan et al., 1996). Lower-elevation records for females compared to 
males also have been reported during summer for northwestern Arizona (Cockrum et al., 1996), 
and a predominance of males at high-elevation forested areas was noted in New Mexico (Bogan et 
al., 1998), and at Mesa Verde National Park, Colorado, where most capture sites were at elevations 
greater than 1,890 m (O’Shea et al., 2011a). 
Foraging and Dietary Analysis. — In north central Oregon, radio-tracked females emerged 
relatively early in relation to sunset and traveled down side canyons and along creeks to common 
foraging areas on the floodplain of the John Day River, from three to 12 kilometers distant from 
their separate roosts (Rodhouse and Hyde, 2014). Surrounding habitat was characterized as juniper 
woodland and sagebrush aridlands, above an area of both irrigated cropland and abandoned fields. 
Six of nine females radio tracked for two to eight nights used the same 2.5-kilometer-long oval 
shaped foraging areas over the floodplain each night, an area also used on some nights by the 
remaining three bats. Radio-tagged bats did not use night roosts, but some returned to day roosts 
for short (approximately 20-minute) periods, presumably to nurse young, whereas later in the sum¬ 
mer females remained away from roosts foraging for about four hours (Rodhouse and Hyde, 2014). 
Females foraged in small circuits about two to five meters high over the floodplain (including irri¬ 
gated crop fields), slopes, rock outcrops, and the river. In the Huachuca Mountains of southeastern 
Arizona, they were observed foraging in the oak woodland vegetation belt of the Upper Sonoran 
desert life zone (Hoffmeister and Goodpaster, 1954). 
In northeastern Oregon, western small-footed myotis are reported to feed primarily on lepi- 
dopterans, hemipterans, and dipterans (Whitaker et al., 1981). Lepidopterans and coleopterans 
were the most often encountered groups seen in dietary analysis of fecal samples from northern 
Arizona ponderosa pine forest, with dipterans, neuropterans, hymenopterans, and hemipterans also 
consumed (Warner, 1985). Dietary analysis of stomach contents of western small-footed myotis 
from northwestern Colorado indicated that coleopterans were the major dietary component, fol¬ 
lowed by lepidopterans and trichopterans in descending order of proportional frequency, with other 
groups of insects each constituting less than 10% (Armstrong et al., 1994). Stomach contents of 
two individuals from southeastern Montana contained finely masticated remains of small beetles, 
lepidopterans, homopterans (cicadellids), dipterans, and trichopterans (Jones et al., 1973). In the 
semi-arid Okanagan Valley of southern British Columbia, analysis of feces from bats captured 
mainly over water revealed predominantly trichopterans, followed by dipterans, lepidopterans and 
coleopterans in descending order of proportional frequency (Woodsworth, 1981). In this region, the 
diet was comparable to the similarly sized, sympatric California myotis, but the two species tend¬ 
ed to forage in different habitats: western small-footed myotis favored areas over rocky bluffs and 
California myotis fed over river banks (Woodsworth, 1981). These observations are similar to ear¬ 
lier notes from the same region that indicated that this species foraged over edges of rock cliffs and 
from one meter above ground to tree height when in wooded areas (Fenton et al., 1980). 
Western small-footed myotis were among the species group sampled by Adams et al. (2003) 
that preferred drinking at watering places with higher concentrations of calcium and other miner¬ 
als, perhaps providing a supplement to dietary intake that would be most critical to reproductive 
females and weaned volant juveniles. 
Roosting Habits. — Winter Roosts: Jagnow (1998) found these bats in hibernation in low 
numbers (seven to 111 bats, varying by year) in small groups ranging in size from solitary indi¬ 
viduals to clusters of up to 25 bats at Torgac Cave, New Mexico. This species also has been report¬ 
ed hibernating in small numbers singly at Crocodile Cave in Kane County, Utah and at Logan Cave 
