PROCEEDINGS OF THE CALIFORNIA ACADEMY OF SCIENCES 
Series 4, Volume 65, Supplement I 
availability of suitable roosts can be a limiting factor for some species in particular habitats (for 
example, Kunz, 1982; Kunz and Lumsden, 2003), with the diversity of available roosting sub¬ 
strates influencing U.S. regional species diversity of bats (for example, Humphrey, 1975). The sec¬ 
tion on roosting habits reviews the literature on generalized knowledge of roosting habits for each 
species of concern, including: substrates used as roosts (for example, rocks, trees, caves); sizes and 
composition of roosting groups; seasonal use of roosts in spring and autumn, summer, and winter; 
and functions of roosts including night roosts, swarming or staging sites, maternity (nursery) 
colonies, or hibemacula. Information is also provided on “roost-switching”, wherein colonies or 
individuals may move among roosts with varying frequency (Lewis, 1995). The section also 
includes su mm aries of specialized information derived from more intensive modem studies, such 
as those that utilize radio telemetry coupled with quantitative habitat models to ascertain important 
features of roosts versus randomly selected structures or landscape features. 
Two main sections round out the species accounts. Population Ecology reviews funda¬ 
mental information pertinent to species life history and demographic traits, including reproduction, 
mortality factors, population trends, or population genetics that may be of interest for future stud¬ 
ies such as those aimed at modeling population dynamics or assessment of trends. Life history traits 
include subheadings with citation of published data regarding reproduction, including litter size 
(sometimes based on surprisingly scant sample sizes), and proportion of adult females that are 
reproductive (natality or fecundity rates) each year. The latter can be quite variable depending on 
ecological conditions during the season of sampling and where the samples are taken. Higher rates 
are typical if bats are sampled at maternity colonies. Lower rates may prevail if females are sam¬ 
pled away from maternity colonies because non-reproductive females may not use maternity 
roosts, and in some species and regions non-reproductive females will use different habitats (for 
example, Cryan et al., 2000). Other life-history variables such as adult survival, juvenile survival, 
or age-specific female reproductive rates (one-year old females may have lower reproductive rates 
than older adults; for example, Davis and Barbour, 1970; O’Shea et al., 2010) are not available for 
most species of bats but are provided in the few cases where they have been estimated. Mortality 
factors are also given, along with other relevant or interesting information such as sex ratios and 
maximum reported longevities. The final two subheadings in the Population Ecology section 
include the limited available information on population trends and population genetics. Monitor¬ 
ing of trends in bat populations has suffered estimation and analytical shortcomings (for example, 
O’Shea and Bogan, 2003), but new count methods and occupancy-based surveys continue to be 
developed and implemented (Loeb et al., 2015; see also individual accounts). Included under trend 
information are reviews of studies that provide occupancy and detectability estimates, and reviews 
of case studies of trials in which other novel sampling methods have been carried out. This section 
also reviews compilations of observations that allow more qualitative appraisals of population 
trend. Information on population genetics emphasizing genetic diversity are given in the section on 
Population Ecology as available. 
A section on Management Practices and Concerns follows, with results of specific stud¬ 
ies aimed at providing management recommendations, or a summary of major conservation con¬ 
cerns that the literature indicates require addressing. A final section, Notes and Comments, 
appears in some accounts. This section adds brief information that may be unusual or of general 
interest that is not described in the other sections within that species account. 
