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PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
more often were in restoration areas than were randomly selected snags (Herder and Jackson, 
2000). Long-legged myotis females (n = 27) radio tracked in east-central Arizona ponderosa pine 
forest roosted in 26 snags (18 in ponderosa pine and 8 in snags of other species), one live Gambel 
oak and a single live Douglas fir, with mean colony sizes of 56 bats observed in exit counts (range 
up to 125; Saunders, 2015). 
Bats in ponderosa pine forests of the Black Hills of South Dakota roosted in ponderosa pine 
snags that were greater in diameter but did not differ in height compared to randomly selected 
snags; tree spacing and numbers of snags were greater in roost plots than in randomly selected 
plots, and more roosts were on south-facing slopes than expected (Cryan et al., 2001). Ten bats 
tracked two to 14 days used 16 roosts (seven in tree snags), averaging 3.4 days per roost with exit 
counts ranging one to 31 bats (Cryan et al., 2001). 
In pinon-juniper woodlands of the Gallinas Mountains of New Mexico, Chung-MacCoubrey 
(1996) found maternity colonies numbering 67-200 individuals roosting in ponderosa pine snags 
or live ponderosa pines with long, vertical cracks and loose bark. These trees were in isolated 
stands or “stringers” along arroyos and at the pinon-juniper woodland-ponderosa pine forest eco- 
tone. Lactating females in mid- to late summer did not roost in colonies but changed roosts daily, 
moving among snags and roosting under sloughing bark. Year-to-year reuse of roosts in trees was 
documented (Chung-MacCoubrey, 2003). A colony of over 33 bats was found roosting under bark 
of a fir tree in the mountains of Jalisco, Mexico (Baker and Phillips. 1965). 
Night Roosts: Long-legged myotis use night roosts after feeding, as has been documented at 
several min es and caves in the Black Hills of South Dakota (Turner, 1974), at bridges and build¬ 
ings in California (Dalquest and Ramage, 1946; Dalquest, 1947a; Pierson et al., 1996b, 2001), at 
bridges and caves in Oregon (Albright, 1959; Perimeter, 1996; Ormsbee and McComb, 1998), and 
at abandoned mines in Colorado (Storz and Williams, 1996; Navo et al., 2002). Night roosting at 
bridges in Oregon primarily involved females gathered in clusters (males tended to roost solitari¬ 
ly) for energetic advantages, particularly during late pregnancy; night roosts were typically warmer 
than ambient air (Perimeter, 1996). 
Population Ecology. — Litter Size, Natality, and Female Reproduction: Mating occurs 
in early autumn, with some first-year males apparently capable of breeding and engaging in swarm¬ 
ing behavior observed at entrances to caves used as hibemacula (Druecker, 1972; Schowalter, 
1980). Not all females are likely to reproduce in their first year of life (Druecker, 1972), but esti¬ 
mates of proportions of one-year-olds that are non-reproductive are unavailable. Birth occurs once 
annually in late spring or early summer. Litter size is one, based on preparation of 101 specimens 
in California (Dalquest and Ramage, 1946) and microscopic examination of reproductive tracts in 
New Mexico (Druecker, 1972). Single fetuses also were found in 14 females from Nevada (Hall, 
1946), five females from Arizona (Cockrum, 1955; Cockrum and Ordway, 1959), three females 
from Colorado and five females from Wyoming (Findley, 1954), five females from western South 
Dakota (Jones and Genoways, 1967; Andersen and Jones, 1971; Turner, 1974), three females from 
mountains of southern Nevada and southern California (Grinnell and Swarth, 1913; Vaughan, 
1954; Deacon et al., 1964), two females from southeastern Montana (Jones et al., 1973), two 
females taken in Jalisco, Mexico (Watkins et al., 1972), and a female from Baja California, Mexi¬ 
co (Jones et al., 1965). 
The proportion of breeding females varies with place of capture (higher at maternity colonies) 
and ecological conditions such as drought or habitat and elevation. Dalquest and Ramage (1946:62) 
noted pregnancy in all of 20 females sampled on 2 June 1945 and “almost all” of 81 females sam¬ 
pled on June 4, 1945 at the maternity roost at old Fort Tejon on the slopes of the Tehachapi Moun¬ 
tains in Kern County, California. Natality of adult females captured at watering places at Mesa 
