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Heterotherms vary their use of torpor and choice of refugia to deal with energetic stresses such as reproductive activity and extreme weather. We hypothesized that a temperate-region bat would vary its use of heterothermy in response to air temperature but use of torpor would also be influenced by reproductive stage and roost choice. To test this hypothesis, we collected data on skin temperatures of female Indiana bats (Myotis sodalis) carrying temperature-sensitive radiotransmitters during the summers of 2013–2015. We also measured internal temperatures and external characteristics of roosts used by these bats. We analyzed the influence of daytime air temperature, roost canopy closure, roost type, and bat reproductive stage, on daily heterothermy index and torpor characteristics of 17 bats during 103 full roost days (data collected consistently from when a bat entered its roost in the morning to when it emerged at night). Our data showed that Indiana bat heterothermy was influenced by reproductive stage, roost choice, and weather. Although they used torpor, pregnant bats were the least heterothermic (daily heterothermy index = 3.3 ± 0.6°C SE), followed by juvenile bats (5.6 ± 0.5°C), lactating bats (5.7 ± 0.5°C), and one postlactating bat (13.2 ± 1.6°C). Air temperature also influenced heterothermy of pregnant bats less than bats of other reproductive stages. Thermoregulatory strategies varied on a continuum from use of normothermia in warm roosts to use of long and deep bouts of torpor in cool roosts. The thermoregulatory strategy used seemed to be determined by potential reproductive costs of torpor and energetic consequences of weather. Because Indiana bats used different degrees of heterothermy throughout the summer maternity season, managers should offer maternity colonies an array of refugia to facilitate varying behaviors in response to weather and energetic demands. [ABSTRACT FROM AUTHOR]

Variation in weather and food availability impacts the energy budgets of endotherms, with some species using torpor as an energy-saving strategy during periods of negative energy balance. We evaluated how latitudinal differences in energy balance relate to variation in torpor expression and roosting sociality between populations. We monitored summer skin temperatures (Tsk) of individuals from 2 populations of New Zealand lesser shorttailed bats (Mystacina tuberculata) separated by 6° of latitude using temperature telemetry. Although mean summer Ta was only < 1°C lower for the higher-latitude than lower-latitude population, individuals living at the higher-latitude site used torpor on 36% of observation days compared to 11% for lower-latitude bats. None of the recorded weather variables affected the propensity to enter torpor or torpor bout duration; however, the minimum torpid Tsk of bats positively correlated with daily minimum Ta. Roosts occupied by solitary bats were warmer than Ta and temperatures within them fluctuated less than Ta. Higher-latitude individuals roosted solitarily (38%) more frequently than lower-latitude individuals (17%) and individuals from both populations exclusively used torpor while roosting solitarily. Arousals from torpor by higher-latitude bats coincided with sunset and not daily Ta maxima suggesting that bats were not fully exploiting advantages of passive rewarming. Site-specific roost choice and torpor patterns were apparent between M. tuberculata populations during summer, demonstrating that small differences in Ta differentially affect energetic strategy. The thermoregulatory behavior of species inhabiting latitudinal gradients in climate is highly plastic, likely to meet the specific challenges of their environment. [ABSTRACT FROM AUTHOR]

This paper is based on an oral presentation delivered at the 89th Annual Meeting of the American Society of Mammalogists in Fairbanks, Alaska on 25 June 2009, where I was honored to receive the Society's Joseph Grinnell Award for excellence in education in mammalogy. The motivation for the topic of my presentation was the many "bad" talks all of us have endured at scientific meetings and in other situations. As I do for undergraduate and graduate classes, rather than providing a list of seminar "dos" and "don'ts," I presented a practical demonstration of many of the "don'ts" I have observed and then attempted to present the same information incorporating as many of the "do's" as I could. In other words, I delivered a bad and then a good version of the same presentation. My goal was to provide the audience with advice that would be useful when presenting information about mammals to scientific colleagues and the general public (e.g., service clubs or school groups). Given that it is impossible to recreate aspects of my performance using the written word, my purpose here is to summarize my opinions about the key elements of good talks. The goal of a talk should be to maximize the likelihood that it will be perceived as interesting, thoughtful, and purposeful and that the key take-home message(s) will be understood and remembered. It is my strongly held belief, especially with the now essentially universal use of computer slideware (e.g., PowerPoint), that an opportunity exists to enhance the usefulness of oral presentations but a real risk of muddling them to the point where the intended message is lost. I also make some recommendations about how to avoid common pitfalls of using this software. [ABSTRACT FROM AUTHOR]

Most recent research on the roosting habits of temperate, forest-living bats has focused on species that use enclosed cavities, but less has been done to address roosting by foliage-living species, which are assumed to have more flexible roost requirements. Numerous studies have suggested that bats select roosts on the basis of microclimate, yet few have tested this hypothesis empirically and gone have addressed the use of foliage roosts in this context. We used radiotelemetry to locate roost sites of reproductive female hoary bats (Lasiurus cinereus) then compared a variety of physical features of these trees with randomly selected nonroost trees. We also recorded ambient temperature and wind speed at roost and nonroost sites to test the hypothesis that physical features associated with foliage roosts provide energetic benefits. Hoary bats selected roost sites on the southeast side of mature white spruce trees (Picea glauca; X orientation 158.6 ± 6.3° SSE), Roost trees were more likely than random trees to be the same height as the surrounding forest canopy: had Less canopy cover facing out from the tree in the direction of the roost branch; and had lower forest density on their southeast side. Wind speed was significantly lower at roosts sites compared with opposite sides of the same trees, presumably due to increased protection from prevailing west winds. Incorporating an estimate of convective cooling due to wind, we predicted daily thermal energy expenditure for normothermic bats and found that selected roost sites provided statistically significant energy savings (up to 1.60 ± 0.99 kJ/day) relative to the predicted expenditures if bats had roosted on the opposite sides of trees. Our results provide direct evidence that hoary bats select forest roosts on the basis of microclimate and suggest that roost requirements of foliage-roosting species may be more specific than has been previously assumed. [ABSTRACT FROM AUTHOR]

Deals with a study which examined the effects of spatially complex habitat or clutter and prey availability on the habitat selection of bats. Materials and methods; Results; Discussion.

Presents information on a study which investigated the effects of moonlight on the activity of bats. Effects of biological rhythms and illumination on nocturnal mammals; Materials and methods; Results of the study.

Presents a study which assessed the roost-site preferences of forest-dwelling California bats (Myotis californicus). Comparison of the characteristics of trees and sites of roost trees; Efforts to determine whether the features of tree roost selected by a variety of bats are similar; Information on the implications.

Previous studies of forest-dwelling bats have identified physical features of trees and forests that correlate with the presence of bats by comparing roost sites to paired, randomly selected sites. This method may be limited if the absence of bats from random sites cannot be confirmed. Our purpose was to address roosting ecology of female big brown bats (Eptesicus fuscus) using a different approach. We quantified relative use of trees with 3 different types of cavity openings (long crevices, multiple holes, or single holes) and compared the relative use of these potential roosts to the availability of each roost type in the study area. Bats used trees with multiple holes and crevices significantly more often than expected based on their availability and trees with single holes less often than expected. Crevice roosts had significantly larger cavities than did single holes and roosting-group size was positively correlated with cavity volume. No relationship was found between cavity volume and tree height or stem diameter of roost trees, 2 variables that have been reported to correlate with roost selection in other studies of forest bats. Examination of our data suggests that the volume of roost cavities may be an important selection criterion for colonial, forest-living bats and that standard interpretations of the roost versus random-tree approach may not accurately identify patterns of roost selection in some systems. [ABSTRACT FROM AUTHOR]

Hoary bats (Lasiurus cinereus) and silver-haired bats (Lasionycteris noctivagans) are species of conservation concern because of the documented annual mortality that occurs at wind energy facilities. Several recent studies have predicted continental-scale declines of hoary bat populations due to interactions with wind turbines. We predicted a decrease in captures at a summer site over 20 years where researchers have captured bats using generally consistent methods. We developed a hierarchical Bayesian model to estimate the relative change in the expected number of captures while controlling for time of year, temperature, and netting effort. We found no decrease in the number of captures for either species. We suggest that the lack of decrease observed at our study site may be a result of compensatory immigration, despite potential broader-scale population declines. [ABSTRACT FROM AUTHOR]

Many bats, including some small-bodied tropical and subtropical Pteropodidae, use torpor to offset energetic constraints. We tested the hypothesis that medium-sized (110-160 g) cave-roosting Egyptian rousette bats (Rousettus aegyptiacus) at the southern extent of their range are able to employ torpor. We measured daytime body temperatures (Tb) of 9 wild individuals using implanted temperature-sensitive radiotransmitters. The bats roosted in a cave on Table Mountain, Cape Town, South Africa (a typically cool and wet area). Daily mean cave temperature (Tc) ranged between 7°C and 12°C (mean 9.3°C). All wild individuals exhibited a circadian cycle in Tb, with an average of 37.7°C upon return from foraging, decreasing to 35.5°C by mid-day. Before emergence for feeding, Tb increased to about 37°C. No individual allowed Tb to drop below 34°C indicating (assuming a threshold temperature of 30°C) that individuals in this population do not use torpor. Bats were active throughout the day within the roost and metabolic heat production may have contributed to the maintenance of rest-phase Tb. Ten individuals implanted with temperature-sensitive passive integrated transponder tags were held in captivity at temperatures of 25-30°C and subjected to food deprivation for 2-3 days. The lowest Tb recorded for any captive individual was 33.4°C despite losing an average of 10% of their initial body mass. Despite exposure to cool Ta in the cave, and often cold, wet, and windy conditions while foraging, or substantial food restriction in captive bats, R. aegyptiacus did not resort to using torpor. [ABSTRACT FROM AUTHOR]