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Sex differences in body color (i.e., sexual dichromatism) are rare in bats and, more broadly, in mammals. The eastern red bat (Lasiurus borealis) is a common tree‐roosting bat that occupies much of North America and has long been described as sexually dichromatic. However, previous research on this species found that absolute body size and collection year were better predictors of fur color in preserved specimens than sex. We revisited this issue and photographed 82 live eastern red bats under standardized conditions, then used image analysis to quantify pelage hue, saturation, and value. We used an information theoretic approach to evaluate four competing hypotheses about the principal drivers of color differences in the fur of eastern red bats. Our analyses demonstrated that sex was a better predictor of pelage color than body size; males had redder, more saturated, and lighter pelages than females. Additionally, the fur color of juvenile versus adult bats differed somewhat, as juveniles were darker than adults. In general, absolute body size (i.e., forearm length in bats) was a poor predictor of color in live eastern red bats. In an exploratory post‐hoc analysis, we confirm that fur color is related to body mass (i.e., a proxy for body condition in bats), suggesting color might serve as a sexually selected signal of mate quality in this partially diurnal species. Future work should investigate the functional role of sexual dichromatism in this species, which could be related to signaling or possibly thermoregulation. [ABSTRACT FROM AUTHOR]

Abstract Sex differences in body color (i.e., sexual dichromatism) are rare in bats and, more broadly, in mammals. The eastern red bat (Lasiurus borealis) is a common tree‐roosting bat that occupies much of North America and has long been described as sexually dichromatic. However, previous research on this species found that absolute body size and collection year were better predictors of fur color in preserved specimens than sex. We revisited this issue and photographed 82 live eastern red bats under standardized conditions, then used image analysis to quantify pelage hue, saturation, and value. We used an information theoretic approach to evaluate four competing hypotheses about the principal drivers of color differences in the fur of eastern red bats. Our analyses demonstrated that sex was a better predictor of pelage color than body size; males had redder, more saturated, and lighter pelages than females. Additionally, the fur color of juvenile versus adult bats differed somewhat, as juveniles were darker than adults. In general, absolute body size (i.e., forearm length in bats) was a poor predictor of color in live eastern red bats. In an exploratory post‐hoc analysis, we confirm that fur color is related to body mass (i.e., a proxy for body condition in bats), suggesting color might serve as a sexually selected signal of mate quality in this partially diurnal species. Future work should investigate the functional role of sexual dichromatism in this species, which could be related to signaling or possibly thermoregulation.

Abstract Along the mid-Atlantic coast of the United States, eastern red bats (Lasiurus borealis) are present during fall mating and migration, though little is currently known about most aspects of bat migration. To reveal migration patterns, and understand drivers of over-water flight, we captured and radio-tagged 115 eastern red bats using novel technology, and subsequently tracked and described their movements throughout the region. We compared over-water flight movements to randomly generated patterns using a use-availability framework, and subsequently used a generalized linear mixed effects model to assess the relationship of over-water flight to atmospheric variables. We used hidden Markov models to assess daily activity patterns and site residency. Most bats with long-distance movements traveled in a southwesterly direction, however path vectors were often oriented interior toward the continental landmass rather than along the coastline. We observed that some bats transited wide sections of the Chesapeake and Delaware bays, confirming their ability to travel across large water bodies. This over-water flight typically occurred in the early hours of the night and during favorable flying conditions. If flight over large water bodies is a proxy for over-ocean flight, then collision risk at offshore wind turbines – a major source of migratory bat fatalities – may be linked nightly to warm temperatures that occur early in the fall season. Risk, then, may be somewhat predictable and manageable with mitigation options linking wind-energy operation to weather conditions and seasonality.

Along the mid-Atlantic coast of the United States, eastern red bats (Lasiurus borealis) are present during fall mating and migration, though little is currently known about most aspects of bat migration. To reveal migration patterns, and understand drivers of over-water flight, we captured and radio-tagged 115 eastern red bats using novel technology, and subsequently tracked and described their movements throughout the region. We compared over-water flight movements to randomly generated patterns using a use-availability framework, and subsequently used a generalized linear mixed effects model to assess the relationship of over-water flight to atmospheric variables. We used hidden Markov models to assess daily activity patterns and site residency. Most bats with long-distance movements traveled in a southwesterly direction, however path vectors were often oriented interior toward the continental landmass rather than along the coastline. We observed that some bats transited wide sections of the Chesapeake and Delaware bays, confirming their ability to travel across large water bodies. This over-water flight typically occurred in the early hours of the night and during favorable flying conditions. If flight over large water bodies is a proxy for over-ocean flight, then collision risk at offshore wind turbines – a major source of migratory bat fatalities – may be linked nightly to warm temperatures that occur early in the fall season. Risk, then, may be somewhat predictable and manageable with mitigation options linking wind-energy operation to weather conditions and seasonality. [ABSTRACT FROM AUTHOR]

Bats are important components of global ecosystems, providing essential ecosystem services with substantial economic benefit. Yet North American bat populations have been negatively affected by numerous factors (e.g., disease, habitat loss, wind energy development) with compounding effects. Bats use habitats at a variety of scales, from small, isolated patches to large, contiguous corridors. Landscape‐level research is necessary to identify important habitats, patches, and corridors to strategically target management interventions. We created habitat suitability models (HSMs) for hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and tri‐colored bats (Perimyotis subflavus) across Illinois, USA, using species‐specific landscape and climate variables. With the 3 models from this study and a previously published HSM for Indiana bats (Myotis sodalis), we stacked binary HSMs, thereby identifying priority conservation areas across Illinois. Species exhibited different distributional patterns and habitat preferences across Illinois. Multi‐species HSMs highlight high quality habitat (i.e., ecologically important habitat that provides preferred resources for roosting, foraging, and raising young) in southern Illinois and along river riparian areas. This approach identified priority conservation areas mainly following hydrologic zones, which allows managers to strategically target restoration and conservation measures, invest funds in habitat likely to have high return‐on‐investment, and assist with decisions that affect bats (e.g., siting wind turbines, purchasing mitigation lands). [ABSTRACT FROM AUTHOR]

White-nose syndrome (WNS) is an emerging fungal epizootic disease that has caused large-scale mortality in several species of North American bats. The fungus that causes WNS, Pseudogymnoascus destructans (Pd), has also been detected in bat species without diagnostic signs of WNS. Although these species could play a role in WNS spread, understanding of the spatial and temporal extents of Pd occurrence on WNS-resistant species is limited. This study evaluated the presence of Pd on 272 individuals of three species of migratory tree-roosting bats: hoary (Lasiurus cinereus), eastern red (Lasiurus borealis), and silver-haired (Lasionycteris noctivagans) bats, obtained opportunistically during summer and autumn from throughout much of their ranges in North America. We also compared tissue sampling protocols (i.e., tissue swabbing, fur swabbing, and DNA extraction of excised wing tissue). We detected Pd on three eastern red bats from Illinois and Ohio, US, one silver-haired bat from West Virginia, US, and one hoary bat from New York, US, all via DNA extracted from wing tissue of carcasses. These results document the first publicly reported detections of Pd on a hoary bat and on migratory bats during the autumn migratory period, and demonstrate the potential for using carcasses salvaged at wind-energy facilities to monitor for Pd. [ABSTRACT FROM AUTHOR]

Abstract Background White-nose Syndrome (WNS) has reduced the abundance of many bat species within the United States’ Mid-Atlantic region. To determine changes within the National Park Service National Capital Region (NCR) bat communities, we surveyed the area with mist netting and active acoustic sampling (2016–2018) and compared findings to pre-WNS (2003–2004) data. Results The results indicated the continued presence of the threatened Myotis septentrionalis (Northern Long-eared bat) and species of conservation concern, including Perimyotis subflavus (Tri-colored bat), Myotis leibii (Eastern Small-footed bat) and Myotis lucifugus (Little Brown bat). However, we documented a significant reduction in the abundance and distribution of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in the abundance of Eptesicus fuscus (Big Brown bat). Conclusions Documented post-WNS M. septentrionalis recruitment suggests that portions of the NCR may be important bat conservation areas. Decreases in distribution and abundance of P. subflavus and M. lucifugus indicate probable extirpation from many previously occupied portions of the region.

Acoustic data are often used to describe bat activity, including habitat use within the summer reproductive period. These data inform management activities that potentially impact bats, currently a taxa of high conservation concern. To understand the relationship between acoustic and reproductive timing, we sampled big brown bats (Eptesicus fuscus) and eastern red bats (Lasiurus borealis) on 482 mist-netting and 35,410 passive acoustic sampling nights within the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia, 2015–2018. We documented the proportion of female, pregnant, lactating, and juvenile big brown and eastern red bats within each mist-net sampling event and calculated locally estimated non-parametric scatterplot smoothing (LOESS) lines for each reproductive and acoustic dataset. We compared the peak in acoustic activity with the peaks of each reproductive condition. We determined that the highest levels of acoustic activity within the maternity season were most associated with the period wherein we captured the highest proportions of lactating bats, not juvenile bats, as often assumed. [ABSTRACT FROM AUTHOR]

White‐nose syndrome (WNS) is a disease caused by the fungus Pseudogymnoascus destructans which has resulted in the deaths of millions of bats across eastern North America. To date, hibernacula counts have been the predominant means of tracking the spread and impact of this disease on bat populations. However, an understanding of the impacts of WNS on demographic parameters outside the winter season is critical to conservation and recovery of bat populations impacted by this disease. We used long‐term monitoring data to examine WNS‐related impacts to summer populations in West Virginia, where WNS has been documented since 2009. Using capture data from 290 mist‐net sites surveyed from 2003 to 2019 on the Monongahela National Forest, we estimated temporal patterns in presence and relative abundance for each bat species. For species that exhibited a population‐level response to WNS, we investigated post‐WNS changes in adult female reproductive state and body mass. Myotis lucifugus (little brown bat), M. septentrionalis (northern long‐eared bat), and Perimyotis subflavus (tri‐colored bat) all showed significant decreases in presence and relative abundance during and following the introduction of WNS, while Eptesicus fuscus (big brown bat) and Lasiurus borealis (eastern red bat) responded positively during the WNS invasion. Probability of being reproductively active was not significantly different for any species, though a shift to earlier reproduction was estimated for E. fuscus and M. septentrionalis. For some species, body mass appeared to be influenced by the WNS invasion, but the response differed by species and reproductive state. Results suggest that continued long‐term monitoring studies, additional research into impacts of this disease on the fitness of WNS survivors, and a focus on providing optimal nonwintering habitat may be valuable strategies for assessing and promoting recovery of WNS‐affected bat populations. [ABSTRACT FROM AUTHOR]

Understanding seasonal variation in the distribution and movement patterns of migratory species is essential to monitoring and conservation efforts. While there are many species of migratory bats in North America, little is known about their seasonal movements. In terms of conservation, this is important because the bat fatalities from wind energy turbines are significant and may fluctuate seasonally. Here we describe seasonally resolved distributions for the three species that are most impacted by wind farms (Lasiurus borealis (eastern red bat), L. cinereus (hoary bat) and Lasionycteris noctivagans (silver-haired bat)) and use these distributions to infer their most likely migratory pathways. To accomplish this, we collected 2,880 occurrence points from the Global Biodiversity Information Facility over five decades in North America to model species distributions on a seasonal basis and used an ensemble approach for modeling distributions. This dataset included 1,129 data points for L. borealis, 917 for L. cinereus and 834 for L. noctivagans. The results suggest that all three species exhibit variation in distributions from north to south depending on season, with each species showing potential migratory pathways during the fall migration that follow linear features. Finally, we describe proposed migratory pathways for these three species that can be used to identify stop-over sites, assess small-scale migration and highlight areas that should be prioritized for actions to reduce the effects of wind farm mortality.

The monitoring of bats across the world is mostly conducted using invasive mist-netting, whereby vertical nets are placed to capture bats mid-flight. Many studies have demonstrated how this approach causes sampling bias, is labor-intensive and increases the risk of white-nose syndrome fungus, Pseudogymnoascus destructans, transmission among bats. Increasingly, acoustic devices are being employed to collect data on bat activity and richness. Community-based monitoring is an important data collection source for bat monitoring programs in countries such as the UK (National Bat Monitoring Program), whereby walking bat transects are conducted using bat detectors. Since the launch of smartphone devices to record and auto-identify bat echolocation calls, the quality of data collection that community members can collect has increased significantly, however, this approach is seldom used to generate data in scientific studies. In our study, we have showcased how our study design paired with state of the art acoustic monitoring devices, can be applied to community-based monitoring of bats across the world. Through employing smartphone acoustic devices, we have determined how primary and secondary vegetation cover are predictors of bat species occurrence and identified the importance of riverine and deciduous swamp habitats for rare bat species in southwestern Ontario. [ABSTRACT FROM AUTHOR]

Background: White-nose Syndrome (WNS) has reduced the abundance of many bat species within the United States' Mid-Atlantic region. To determine changes within the National Park Service National Capital Region (NCR) bat communities, we surveyed the area with mist netting and active acoustic sampling (2016–2018) and compared findings to pre-WNS (2003–2004) data. Results: The results indicated the continued presence of the threatened Myotis septentrionalis (Northern Long-eared bat) and species of conservation concern, including Perimyotis subflavus (Tri-colored bat), Myotis leibii (Eastern Small-footed bat) and Myotis lucifugus (Little Brown bat). However, we documented a significant reduction in the abundance and distribution of M. lucifugus and P. subflavus, a decrease in the distribution of M. septentrionalis, and an increase in the abundance of Eptesicus fuscus (Big Brown bat). Conclusions: Documented post-WNS M. septentrionalis recruitment suggests that portions of the NCR may be important bat conservation areas. Decreases in distribution and abundance of P. subflavus and M. lucifugus indicate probable extirpation from many previously occupied portions of the region. [ABSTRACT FROM AUTHOR]

Understanding seasonal variation in the distribution and movement patterns of migratory species is essential to monitoring and conservation efforts. While there are many species of migratory bats in North America, little is known about their seasonal movements. In terms of conservation, this is important because the bat fatalities from wind energy turbines are significant and may fluctuate seasonally. Here we describe seasonally resolved distributions for the three species that are most impacted by wind farms (Lasiurus borealis (eastern red bat), L. cinereus (hoary bat) and Lasionycteris noctivagans (silver-haired bat)) and use these distributions to infer their most likely migratory pathways. To accomplish this, we collected 2,880 occurrence points from the Global Biodiversity Information Facility over five decades in North America to model species distributions on a seasonal basis and used an ensemble approach for modeling distributions. This dataset included 1,129 data points for L. borealis, 917 for L. cinereus and 834 for L. noctivagans. The results suggest that all three species exhibit variation in distributions from north to south depending on season, with each species showing potential migratory pathways during the fall migration that follow linear features. Finally, we describe proposed migratory pathways for these three species that can be used to identify stop-over sites, assess small-scale migration and highlight areas that should be prioritized for actions to reduce the effects of wind farm mortality. [ABSTRACT FROM AUTHOR]

Acoustic data are often used to describe bat activity, including habitat use within the summer reproductive period. These data inform management activities that potentially impact bats, currently a taxa of high conservation concern. To understand the relationship between acoustic and reproductive timing, we sampled big brown bats (Eptesicus fuscus) and eastern red bats (Lasiurus borealis) on 482 mist-netting and 35,410 passive acoustic sampling nights within the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia, 2015–2018. We documented the proportion of female, pregnant, lactating, and juvenile big brown and eastern red bats within each mist-net sampling event and calculated locally estimated non-parametric scatterplot smoothing (LOESS) lines for each reproductive and acoustic dataset. We compared the peak in acoustic activity with the peaks of each reproductive condition. We determined that the highest levels of acoustic activity within the maternity season were most associated with the period wherein we captured the highest proportions of lactating bats, not juvenile bats, as often assumed.

Temperate bat species cope with environmental temperatures outside their thermoneutral zone through physiological responses, habitat selection, and social roosting. While there have been several studies examining these factors in bat species that form maternity colonies in tree cavities, underneath bark, or in manmade structures, such studies rarely focus on bats that roost solitarily in tree foliage. To better understand the thermal environment of a foliage‐roosting bat and how they respond to thermal stimuli, we used temperature‐sensitive radio‐telemetry and environmental dataloggers to study the eastern red bat (Lasiurus borealis) in southeast Ohio. We collected skin temperatures from eight male and nine reproductive female bats in combination with microclimate data from 25 bat roosts and 15 random trees. We found that elevation, minimum ambient temperature, and maximum ambient temperature best predicted bat skin temperatures, while sex had little effect. We also found that trees located at higher elevations had warmer canopy microclimates than those at lower elevations, but temperatures did not differ between roost and random trees. These results show that solitary, foliage‐roosting species use torpor extensively in response to cool temperatures during summer. These results have conservation implications, indicating that areas on the landscape with warmer conditions are important for reducing the cost of maintaining euthermic body temperatures. In southeastern Ohio, this includes upland forests, but our data suggest that temperatures at slope positions, and not the elevation itself, are the important habitat feature for eastern red bats. [ABSTRACT FROM AUTHOR]

The expansion of the wind energy industry has had benefits in terms of increased renewable energy production but has also led to increased mortality of migratory bats due to interactions with wind turbines. A key question that could guide bat-related management activities is identifying the geographic origin of bats killed at wind-energy facilities. Generating this information requires developing new methods for identifying the geographic sources of individual bats. Here we explore the viability of assigning geographic origin using trace element analyses of fur to infer the summer molting location of eastern red bats (Lasiurus borealis). Our approach is based on the idea that the concentration of trace elements in bat fur is related through the food chain to the amount of trace elements present in the soil, which varies across large geographic scales. Specifically, we used inductively coupled plasma–mass spectrometry to determine the concentration of fourteen trace elements in fur of 126 known-origin eastern red bats to generate a basemap for assignment throughout the range of this species in eastern North America. We then compared this map to publicly available soil trace element concentrations for the U.S. and Canada, used a probabilistic framework to generate likelihood-of-origin maps for each bat, and assessed how well trace element profiles predicted the origins of these individuals. Overall, our results suggest that trace elements allow successful assignment of individual bats 80% of the time while reducing probable locations in half. Our study supports the use of trace elements to identify the geographic origin of eastern red and perhaps other migratory bats, particularly when combined with data from other biomarkers such as genetic and stable isotope data.

Relatively high mortality of migratory bats at wind energy facilities has prompted research to understand the underlying spatial and temporal factors, with the goal of developing more effective mitigation approaches. We examined acoustic recordings of echolocation calls at 12 sites and post-construction carcass survey data collected at 10 wind energy facilities in Ontario, Canada, to quantify the degree to which timing and regional-scale weather predict bat activity and mortality. Rain and low temperatures consistently predicted low mortality and activity of big brown bats (Eptesicus fuscus) and three species of migratory tree bats: hoary bat (Lasiurus cinereus), eastern red bat (L. borealis), and silver-haired bat (Lasionycteris noctivagans). Bat activity occurred in waves with distinct peaks through the season; regardless of seasonal timing, most activities occurred in the first half of the night. We conclude that wind energy facilities could adopt a novel and more effective curtailment strategy based on weather and seasonal and nocturnal timing that would minimize mortality risks for bats while increasing the opportunities for power generation, relative to the mitigation strategy of increasing cut-in wind speed to 5.5 m/s.

Most species of bats give birth to only 1 pup each year, although Eastern red bats (Lasiurus borealis) can produce up to 5 pups per litter. Offspring in a single litter have been documented to be at different stages of development, suggesting that multiple paternity occurs. We tested the null hypothesis of genetic monogamy in red bats using 6 autosomal microsatellites and 1 X-linked microsatellite from 31 parent/offspring groups for a total of 128 bats. We sampled both pregnant females and mothers with pups that were obtained from bats submitted to departments of health in Oklahoma and Texas for rabies testing. Multiple paternity was assessed using a maximum-likelihood approach, hypothesis testing, and X-linked locus exclusion. The mean polymorphic information content of our markers was high (0.8819) and combined non-exclusion probability was low (0.00027). Results from the maximum-likelihood approach showed that 22 out of 31 (71%) parent/offspring groups consisted of half siblings, hypothesis testing rejected full sibship in 61% of parent/offspring groups, and X-linked locus exclusion suggested multiple paternity in at least 12 parent/offspring groups, rejecting our hypothesis of genetic monogamy. This frequency of multiple paternity is the highest reported thus far for any bat species. High levels of multiple paternity have the potential to impact interpretations of genetic estimates of effective population size in this species. Further, multiple paternity might be an adaptive strategy to allow for increased genetic variation and large litter size, which would be beneficial to a species threatened by population declines from wind turbines. [ABSTRACT FROM AUTHOR]

Bat fatality at wind energy facilities is a conservation issue, but its effect on bat populations is difficult to estimate. We have little understanding of wind turbine effects on bat population persistence, in part because we have poor knowledge of bat migration pathways and hence the source populations for individual fatalities. We used deuterium ratio analysis combined with genetic algorithm for rule‐set prediction and the web‐based isoscapes modeling, analysis, and prediction in a geographic information system environment as a novel approach. Our objectives were to explore the utility of these methods together and map the geographic extents of eastern red bat (Lasiurus borealis) specimens salvaged in 2008–2010 from a single, 92‐km2 wind energy facility in Illinois, USA. Results indicate that combining these methods can be successful and support their use with species where ranges may be less well defined. Because of the migratory nature of this species and the range of deuterium values of pixels in our isotope model, we predicted that 18% and 82% of the specimens would have isotope results inside and outside of the wind facility's isocline respectively. We concluded that 71.4% of the specimens had isotope signatures placing them outside the wind facility's isocline. It could be argued that the wide distribution of bat fatalities dilutes the overall effect of those fatalities on the bat species; however, if other facilities show a similar pattern, each facility could have cumulative and far reaching population‐level effects. © 2019 The Wildlife Society. The combination of isotopes and niche modeling, using existing museum and wind farm‐salvaged specimens, represents a viable alternative for characterizing the movement patterns and ranges of migratory bat species. Furthermore, the combination of these methods is an option for other species whose ranges are less well known. [ABSTRACT FROM AUTHOR]

White-nose syndrome (WNS) affects bats primarily in winter, with Pseudogymnoascus destructans, the fungus that causes WNS, growing on bats in colder climates as they are hibernating. As a result, nearly all disease investigations have been conducted on bats in the winter or as they are emerging in spring. Although P. destructans has been detected on bats during the summer season, the seasonal dynamics of infection during this period remain poorly understood. To test for the presence of P. destructans during the summer season, we sampled bats that were free flying from June 2017 to September 2017 and also sampled bats from a maternity roost in August and outside a known hibernaculum in September. We collected skin swabs from the muzzle and forearm of bats, and using real-time PCR methods, we detected P. destructans DNA on 16% (12/76) of bats sampled in Wisconsin, US, including juvenile little brown bats (Myotis lucifugus) from bat house maternity roosts, and free-flying adult bats of two species captured in June, the little brown bat and the migratory eastern red bat (Lasiurus borealis). These data illustrated the potential for P. destructans to be transferred and dispersed among bats during the summer and highlighted the complex seasonal dynamics associated with this pathogen. [ABSTRACT FROM AUTHOR]

Carcasses provide an important resource for assessing the vulnerability of bat species and sexes to threats, but the reliability of sex data derived from the external morphology (sexmorph) of bat carcasses remains uncertain. We used genetic‐based assessment of sex (sexgen) to evaluate the effect of carcass age and searcher identity on sexmorph‐based assessments of eastern red (Lasiurus borealis) and hoary (Lasiurus cinereus) bat carcasses identified by 15 different searchers at a wind‐energy facility. The proportion of carcasses for which sexmorph was unknown increased from 0.11 for those recovered within a day of death, to 0.56 within 2–3 days of death, and to ≥0.82 at ≥4 days after death. The proportion of carcasses for which sexmorph was correct decreased from 0.9 for those recovered within a day of death, to 0.65 within 2–3 days of death, and to 0.25 at ≥4 days after death. The proportion of sexmorph misidentifications of the 108 fresh carcasses (collected within 24 hours of death) varied (0.0–0.43) among searchers. These results suggest that sexmorph‐based assessments should be limited to fresh carcasses. Furthermore, additional training of people who collect and identify bat carcasses from renewable‐energy facilities may improve the accuracy of sexmorph data obtained from carcasses. © 2018 The Wildlife Society. Morphology‐based identification of the sex of bat carcasses obtained from renewable‐energy facilities should be limited to fresh (<1 day old) carcasses, and searcher training may help to further improve the accuracy of sex data obtained from such carcasses. [ABSTRACT FROM AUTHOR]

• We need more data on the behaviors of forest-dependent bats in managed forests. • We tracked eastern red bats as they foraged and roosted in managed hardwood forests in Indiana, USA. • Both sexes foraged in small areas, roosting in tall trees in uncluttered stands. • Management openings, ponds, and corridors were selected for roosting and foraging. • Eastern red bats can coexist with and could benefit from timber management. Forests provide crucial foraging and roosting habitat to many bat species, and the gradual loss of forests is among the principal threats to global bat diversity. Forests that persist in the face of land use change are those that are managed for a variety of uses, including recreation, hunting, timber production, and wildlife conservation. Thus, understanding how bats respond to management is imperative to their conservation. We used radio telemetry to study the roosting and foraging behaviors of male and female eastern red bats (Lasiurus borealis). These forest-dependent bats roost in the foliage of live trees and are declining across their range. We tracked 26 bats (7 males and 18 females; one female was tracked twice) from May to August 2017–2019 in two state forests in south-central Indiana, USA. We estimated space use with 95% kernel density estimates and used generalized linear and linear mixed models to assess resource selection and use at three levels: population-level foraging selection, individual-level foraging use, and population-level roost selection. On average, eastern red bats foraged over a relatively small area (81 ha) and traveled a maximum distance of 1404 m from their roosts. The eastern red bat population foraged near maintained openings, recent regeneration openings, roads, and ponds within the study area. Within their foraging ranges, eastern red bats spent more time foraging near roads, ponds, and ridges. Eastern red bats roosted near maintained openings, recent regeneration openings, and ponds, switching roosts every two days. Roost trees were larger than random trees and were in plots containing fewer live stems than random plots. Together, these results reveal that some of the most important landscape features for eastern red bats are linear corridors (e.g., roads or ridgetops), forest openings (e.g., maintained openings and recent regeneration openings), perennial sources of water (e.g., ponds), and large trees. Overall, eastern red bats exhibited strong selection for managed portions of the forest, suggesting they can coexist with and likely benefit from timber management. When considering habitat for eastern red bats in central hardwood forests, we recommend land managers work to maintain large tracts of mature (>90 years old) forest, interspersed with young regeneration openings and provisioned with perennial water sources (e.g., ponds). [ABSTRACT FROM AUTHOR]

An unanticipated impact of wind-energy development has been large-scale mortality of insectivorous bats. In eastern North America, where mortality rates are among the highest in the world, the hoary bat ( Lasiurus cinereus) and the eastern red bat ( L. borealis) comprise the majority of turbine-associated bat mortality. Both species are migratory tree bats with widespread distributions; however, little is known regarding the geographic origins of bats killed at wind-energy facilities or the diversity and population structure of affected species. We addressed these unknowns by measuring stable hydrogen isotope ratios (δ2H) and conducting population genetic analyses of bats killed at wind-energy facilities in the central Appalachian Mountains ( USA) to determine the summering origins, effective size, structure, and temporal stability of populations. Our results indicate that ~1% of hoary bat mortalities and ~57% of red bat mortalities derive from non-local sources, with no relationship between the proportion of non-local bats and sex, location of mortality, or month of mortality. Additionally, our data indicate that hoary bats in our sample consist of an unstructured population with a small effective size ( Ne) and either a stable or declining history. Red bats also showed no evidence of population genetic structure, but in contrast to hoary bats, the diversity contained in our red bat samples is consistent with a much larger Ne that reflects a demographic expansion after a bottleneck. These results suggest that the impacts of mortality associated with intensive wind-energy development may affect bat species dissimilarly, with red bats potentially better able to absorb sustained mortality than hoary bats because of their larger Ne. Our results provide important baseline data and also illustrate the utility of stable isotopes and population genetics for monitoring bat populations affected by wind-energy development. [ABSTRACT FROM AUTHOR]

Bats face numerous threats associated with global environmental change, including the rapid expansion of wind-energy facilities, emerging infectious disease, and habitat loss. An understanding of the movement and migration patterns of these highly dispersive animals would help reveal how spatially localized the impacts from these threats are likely to be on bat populations, thus aiding in their conservation. Stable hydrogen isotope ratios (δ2H) can be used to infer regions where bats have foraged during the summer molt season, thus allowing an assessment of summering location and distance of movement of bats sampled during other times of year. However, a major impediment to the application of δ2H for inference of bat movements is that the relationship between δ2H of bat hair and precipitation tends to be species specific and is still unknown for some key species of conservation concern. We addressed this issue by using geo-referenced museum specimens to calibrate the relationship between δ2H of hair (δ2Hhair) and long-term δ2H of growing-season precipitation (δ2HGSprecip) at the site of collection for eastern red bats (Lasiurus borealis), one of the main species of bats experiencing large numbers of fatalities at wind-energy facilities in North America. Based on comparison of δ2Hhair and δ2HGSprecip values for males we estimated a period of molt of June 14–August 7. Within this period, male and female red bats exhibited a significant positive relationship between δ2Hhair and δ2HGSprecip. These results establish the relationship between δ2Hhair and δ2HGSprecip for red bats, which is necessary for the use of δ2Hhair to infer the movement and migration patterns of this important species. These results provide a critical resource to conservation biologists working to assess the impacts of environmental change on bat populations.

Migratory tree bats comprise the majority of casualties at wind energy facilities across North America and some species, like Lasiurus borealis, are suspected to be in decline. We took advantage of the large numbers of L. borealis and L. cinereus salvaged during fall migration at 1 wind farm in Texas and 3 wind farms in Minnesota to evaluate the ability of current genetic methods to estimate population size and detect genetic bottlenecks in these species. Using DNA extracted from wing membrane tissue samples, we genotyped 439 L. borealis and 246 L. cinereus at 6 microsatellite loci and a 550 bp segment of the mitochondrial COI gene. Both microsatellite loci and mitochondrial haplotypes showed high levels of genetic diversity in each species. Historical estimates of Ne were large for both species. Estimates of NEf from the COI gene were almost 2 times higher for L. borealis than L. cinereus, whereas estimates utilizing microsatellite heterozygosity were higher for L. cinereus. We found a strong signal of rapid historical population growth and range expansion in L. borealis, but not in L. cinereus. The majority of our estimates of current Ne had upper 95% confidence intervals that encompassed infinity. There is some indication from contemporary estimates of Ne that L. borealis may have a lower current Ne than historical estimates and that L. cinereus may currently have a very large Ne. We found no genetic evidence of recent population declines and no evidence of population structure in either species. Genetic monitoring of migratory tree bats, specifically for the purpose of detecting population declines caused by wind turbine mortality, may be impractical due to the large effective population sizes and high levels of gene flow in these species. Future efforts should focus on developing genomic resources for these species, obtaining better estimates of mutation rates, and conducting range-wide population genetic studies in order to better estimate historical and current population sizes. [ABSTRACT FROM AUTHOR]

Some bat species, including eastern red bats (Lasiurus borealis), roost for short periods beneath leaf litter on the forest floor during winter in the south-eastern USA, a region subjected to frequent fire. The variability in fuel consumption, the heterogeneous nature of burns, and the effects of litter and duff moisture on forest-floor temperatures during winter burning could influence potential survival for bats beneath the leaf litter if they are unable to escape on-coming flames. We measured temperatures below leaf litter in 64 south-slope plots during nine controlled burns in the Ouachita Mountains of Arkansas to determine the probability of survival. Maximum temperature recorded under leaf litter at each plot averaged 292°C (±20 s.e.) and ranged from 10 to 717°C. Only three (5%) of the plots experienced temperatures that were deemed survivable (<60°C sustained for 60 s) during burns on warmer winter days (air temperatures 15.0-26.1°C). Temperatures below the leaf litter measured just before the arrival of fire (average = 19.6°C) suggested that if bats were roosting in plots they would have been in shallow torpor, which would have enabled faster escape from approaching flames. Burning during the warmer periods of winter (e.g. ≥15°C) and during afternoons could potentially improve survival by bats roosting under leaf litter by reducing arousal and escape times. [ABSTRACT FROM AUTHOR]

We monitored pre-construction bat acoustic activity from 2007 to 2010 at 4 wind energy sites in northeastern British Columbia to determine nightly and seasonal activity patterns, relative detection rates of different species groups, and the implications for potential fatalities at northern wind facilities. Mean activity rates (August to September) ranged from 2.4 to 79.4 passes per detector-night at the 4 study areas. Activity differed between years for 3 study areas with multi-year data. Nightly variation in activity was pronounced, with wind speed and temperature recorded at meteorological towers explaining 47 to 61% of the variation in nightly activity. Detections were predominantly (60 to 96%) of Myotis bats. Only 1 to 18% of passes recorded at study areas were low-frequency bats (Big Brown Bat, Eptesicus fuscus; Silver-haired Bat, Lasionycteris noctivagans; Hoary Bat, Lasiurus cinereus), with L. cinereus accounting for <1% of the low-frequency passes. No Eastern Red Bats (Lasiurus borealis) were detected. Seasonal activity of low-frequency bats showed no evidence of an influx of spring migrants, but single-night activity spikes in late August and early September were suggestive of autumn migration. Activity of Myotis bats was highest in August and early September, a pattern consistent with resident populations. Results suggest that Myotis species may form a larger proportion of fatalities at northern wind energy facilities than at sites in more temperate regions. [ABSTRACT FROM AUTHOR]

Little is known about the distribution of Eastern Red Bats (Lasiurus borealis) at the northwestern edge of their range. We compiled and examined a data set of Eastern Red Bat capture and acoustic records from northern Alberta to examine their distribution, seasonality, and reproductive status near the edge of their range. Acoustic data suggested widespread but patchy distribution across Alberta. The number of captures of Eastern Red Bats in northern Alberta were similar to those of Hoary Bat (Lasiurus cinereus), suggesting that the species may be more common than previously thought. However, we failed to find evidence of reproduction in female Eastern Red Bats in Alberta. Small sample sizes, timing of surveys or difficulty in recognizing juveniles may explain the apparent lack of reproduction. Similar to Hoary Bats, reproductive adult male Eastern Red Bats have been captured with enlarged testes in northern Alberta in August, suggesting sperm production and possibly the start of breeding is taking place there in late summer. In northern Alberta, acoustic monitoring in early spring provided evidence of migratory bats early in the season. A better understanding of seasonal movement patterns and migration, habitat use, and reproduction of Eastern Red Bats in western Canada will require further study. Regardless, our data provide further evidence that the Eastern Red Bat is a more regular member of the bat fauna of northwestern Canada than previously recognized, which may be a result of an expanding distribution. [ABSTRACT FROM AUTHOR]

Relatively little is known about bats or bat hibernacula in northern Canada. We were interested in documenting species diversity and seasonal activity of bats in Wood Buffalo National Park, including use of a cave hibernaculum by Little Brown Myotis (Myotis lucifugus), Northern Myotis (Myotis septentrionalis), and Big Brown Bats (Eptesicus fuscus). We used acoustic monitoring and mist netting over 3 y to assess species diversity and seasonal activity. We also recorded cave temperature during hibernation. During the summers of 2010 to 2012, we captured 470 bats including M. lucifugus, M. septentrionalis, and E. fuscus. We identified 2 migratory species via echolocation recordings in 2011: Lasiurus cinereus (Hoary Bat) was recorded in the area from mid-May to early October, and Lasiurus borealis (Eastern Red Bat) from mid-June to early August. Resident bat activity at the hibernaculum was greatest from mid-June to early September. Our findings provide a first approximation of species diversity and describe seasonal activity patterns of bats in Wood Buffalo National Park. [ABSTRACT FROM AUTHOR]

Conserving migratory species is difficult because wide-ranging animals are challenging to study and aspects of their annual cycles occur in geographically distant areas. This challenge is illustrated by the hundreds of thousands of migratory bats killed annually during autumn migration by industrial wind turbines. It is unknown why bats are killed at turbines because they are so difficult to observe during migration. A conservation behaviour approach has potential to explain what is, arguably, the most significant environmental impact of wind energy. We tested predictions of two hypotheses to explain the presence of bats at turbines: (1) bats are attracted to visually conspicuous tall structures during autumn migration; (2) attraction is linked to social behaviour rather than foraging. We compared acoustic activity of migratory tree bats at conspicuous tall structures (telecommunication towers) to activity at two types of control sites (woodlot edges: consistently attractive to bats; open fields: consistently unattractive) before and during migration. Activity of migratory bats increased dramatically at towers during migration, from low premigration levels, to exceed that at open fields and match that at woodlots. Moreover, the proportion of feeding calls at towers remained low while the proportion of events during which multiple bats visited the towers simultaneously increased during migration to surpass that at woodlots and open fields. This suggests that migratory bats actively visit tall structures during migration for reasons other than foraging. Exploiting this behaviour, and the abundance of communication towers on the landscape, could reveal critical information about migratory behaviour of bats and help guide site selection for wind energy projects. Our findings demonstrate the importance of understanding the behaviour of migratory species at all stages of their annual cycle for effective conservation. [ABSTRACT FROM AUTHOR]