Bat Populations Research Articles

One ring does not fit all: Evaluation of banding‐related injuries in tricolored bats

AbstractThe potential harm inflicted by forearm bands on bats has been debated for decades. To aid in decision‐making regarding bat marking, we conducted a comprehensive assessment of banding injuries using recapture data from a long‐term overwintering study in Georgia, USA, involving 776 banded tricolored bats (Perimyotis subflavus) with 284 recaptures. Most recaptured bats showed no visible injuries (77.8%); however, 22.2% of bats presented varying degrees of band‐related injuries. Although <25% of tricolored bats exhibited banding‐related injuries, sublethal effects of injuries are unknown and could add additional stressors to bat populations already facing multiple threats, including mortality from white‐nose syndrome. Thus, we recommend that banding bats, especially species that have experienced white‐nose syndrome‐related population declines, be appropriately justified and their use carefully considered. Our study contributes valuable knowledge to aid in informed decision‐making on the use of capture‐mark‐recapture methods in the research and management of bat communities.

Unveiling bat-borne viruses: a comprehensive classification and analysis of virome evolution.

Bats (Order Chiroptera) are an important reservoir of emerging zoonotic microbes, including viruses of public health concern such as henipaviruses, lyssaviruses, and SARS-related coronaviruses. Despite the continued discovery of new viruses in bat populations, a significant proportion of these viral agents remain uncharacterized, highlighting the imperative for additional research aimed at elucidating their evolutionary relationship and taxonomic classification. In order to delve deeper into the viral reservoir hosted by bats, the present study employed Next Generation Sequencing (NGS) technology to analyze 13,105 swab samples obtained from various locations in China. Analysis of 378 sample pools revealed the presence of 846 vertebrate-associated viruses. Subsequent thorough examination, adhering to the International Committee on Taxonomy of Viruses (ICTV) criteria for virus classification, identified a total of 120 putative viral species with the potential to emerge as novel viruses, comprising a total of 294 viral strains. Phylogenetic analysis of conserved genomic regions indicated the novel virus exhibited a diverse array of viral lineages and branches, some of which displayed close genetic relationships to known human and livestock pathogens, such as poxviruses and pestiviruses. This study investigates the breadth of DNA and RNA viruses harbored by bats, delineating several novel evolutionary lineages and offering significant contributions to virus taxonomy. Furthermore, the identification of hitherto unknown viruses with relevance to human and livestock health underscores the importance of this study in encouraging infectious disease monitoring and management efforts in both public health and veterinary contexts. Video Abstract.

Plain-nosed bats (family Vespertilionidae) as a possible reservoir of lyssaviruses and coronaviruses in Western Siberia and the south of European Russia.

The review presents current data on the chiropterofauna inhabiting Western Siberia and the south of the European part of Russia. A general description of the genus of lyssaviruses and the family of coronaviruses is given. The potential for virus carriage in relation to lyssaviruses and coronaviruses in bat populations of two geographically distant regions is considered.

DNA metabarcoding analyses reveal fine-scale microbiome structures on Western Canadian bat wings.

Microbiomes play important roles in host health. White-nose syndrome (WNS), a fungal infection of bat wings and muzzles, has threatened bat populations across North America since 2006. Recent research suggest that the skin microbiome of bats may play a significant role in bat's susceptibility to WNS. However, relatively little is known about the skin microbiome composition and function in bats in Western Canada, a region with a high diversity of bats, but WNS has yet to be a major issue. Here, we revealed high bacterial and fungal diversities on the skin of three common bat species in Lillooet, British Columbia, including several highly prevalent microbial species that have been rarely reported in other regions. Our analyses showed fine-scale structures of bat wing microbiome based on local sites and bat species. The knowledge obtained from WNS-naïve bat populations in this study may help develop mitigation and management strategies against WNS.

Application of the MENTOR model to advance One Health by promoting bat conservation and reducing zoonotic spillover risk

For few taxonomic groups do conservation efforts have such a disproportionate impact on biodiversity and human well-being as they do with bats. Bats face significant conservation challenges that affect their long-term viability, inhibit their ecosystem functions and services, and increase zoonotic spillover risks. Protecting bat populations and their habitats ultimately reduces these conservation threats, helps prevent pandemics, and supports essential ecosystem services. MENTOR-Bat is a fellowship program focused on strengthening technical research, and leadership capacity in the Global South to promote healthy environments where bats and humans can coexist with reduced risks of pathogen transmission. Co-designed by the United States Fish and Wildlife Service (USFWS) and Bat Conservation International (BCI), MENTOR-Bat mirrors the One Health framework by featuring a transdisciplinary team of three mentors and nine fellows from Cameroon, Colombia, and Indonesia. Fellows and mentors receive academic and field-based training on bat ecology and conservation, One Health, human dimensions of conservation, behavior change, strategic communications, international policy, adaptive management, project planning, conservation leadership, and public health. Fellows will then design and implement team pilot projects to advance One Health and bat conservation in their respective countries. Program evaluation of MENTOR-Bat is based on Kirkpatrick’s Hierarchy and focuses on measuring the development of established One Health core competences. By incorporating One Health and conservation within its activities, MENTOR-Bat can become a valuable programmatic template for transdisciplinary programming advancing evidence-based strategies for improving the well-being of bats, humans, and the environment.

Vulnerability of Southern Hemisphere bats to white-nose syndrome based on global analysis of fungal host specificity and cave temperatures.

White-nose syndrome (WNS), a disease affecting hibernating bats, is caused by the fungal pathogen Pseudogymnoascus destructans (Pd). Since the initial introduction of Pd from Eurasia to the United States in 2006, WNS has killed millions of bats throughout the temperate parts of North America. There is concern that if Pd is accidentally introduced to the Southern Hemisphere, WNS could pose similar threats to the bat fauna of the Southern Hemisphere's more temperate regions. Efforts are required to better understand the vulnerability of bats globally to WNS. We examined phylogenetic distances among cave roosting bat species globally to estimate the probability of infection by Pd. We predicted cave thermal suitability for Pd for 441 cave-roosting bat species across the globe via spatial analysis. We used host specificity models based on 65 species tested for Pd to determine phylogenetic specificity of Pd. Phylogenetic distance was not an important predictor of Pd infection, confirming that Pd has low host specificity. We found extensive areas (i.e., South America, Africa, and Australia) in the Southern Hemisphere with caves that were suitable for cave-roosting bat species and for Pd growth. Hence, if Pd spreads to the Southern Hemisphere, the risk of exposure is widespread for cave-roosting bats, and infection is possible regardless of relatedness to infected species in the Northern Hemisphere. Predicting the consequences of infection remains difficult due to lack of species-specific information about bat winter biology. Nevertheless, WNS is an important threat to naive Southern Hemisphere bat populations. Hence, biosecurity measures and planning of management responses that can help prevent or minimize a potential WNS outbreak in the Southern Hemisphere are urgently needed.

Acoustic study of urban bat diversity in Veliko Tarnovo, Bulgaria

Urbanisation presents both challenges and opportunities for bat populations. Understanding the composition and distribution of urban bat species is the first step toward their effective conservation. However, comprehensive studies on urban bat diversity remain scarce in Bulgaria. To address this gap, we conducted a year-long acoustic survey on five different habitats in the urbanised territory of Veliko Tarnovo. Our study identified the presence of eight bat species and other distinct acoustic groups within the urban environment. Bats were found to utilise various habitats across the urban landscape. Although the activity was highest during May and September, bats remained active all year round, including the winter. Our study provides insights into synanthropic bats’ seasonal and microhabitat-dependent use of urban areas. These findings will establish a baseline for future research focusing on habitat preferences, population dynamics, and interactions with urbanisation. Such research is essential for the effective management and conservation of bat populations in urban environments.

Maximizing benefits to bat populations through management of power line corridors

Abstract Power line corridors are ubiquitous worldwide and are commonly used by bats as habitat. Targeted management of these corridor habitats has the potential to aid bat populations, which is critically important given the multifaceted threats facing bat species, including the emerging infectious disease white‐nose syndrome (WNS) in North America. Here, we review known and potential impacts of management of existing power line corridors on three bat behaviours: foraging, roosting and commuting. We also identify bats in the United States that would benefit from changes to management of power line corridors for improvements to roosting and foraging habitats, particularly species of conservation concern that roost and forage along forest edges. Key recommendations are to avoid disturbance to roosting bats when maintaining vegetation along power line corridors, apply integrated vegetation management to maximize native plant diversity to improve prey options for bats and apply targeted interventions (e.g. artificial roost creation, creation of ponds) in a well‐justified ecological context. Practical implication. We highlight high‐priority research topics to fill knowledge gaps, including testing whether vegetation management treatments targeting plant and insect communities increase bat fitness and cause positive population‐level responses in focal bat species. We conclude that building evidence on how bats are affected by power line corridor management is a conservation need.

Individual variation in breeding phenology and postnatal development in northern bats (Eptesicus nilssonii).

Bats inhabiting northern latitudes are faced with short reproductive seasons during which they must produce and rear pups before fattening up in time to survive the winter hibernation. Therefore, the timing of parturition has considerable impacts on future fitness prospects for the mother and pup. However, little is known about individual variation in breeding phenology and its consequences for postnatal development within bat populations. Here, we studied the phenology of breeding in Eptesicus nilssonii across 7 years using data collected by day-to-day monitoring of a breeding colony in Norway (60.1° N) for which the identity and age of each mother (N = 8) and pup (N = 28) were known. Using mixed-effect models, we found that arrival at the colony was influenced by temperature conditions from mid-April to mid-May across all females, but that there were strong and consistent individual differences in arrival- and parturition time across years. Females generally arrived ~32.1 days before giving birth, but the gestation duration was reduced if females arrived late and prolonged if females left the colony when faced with cold weather conditions. Pups born later in the season were born smaller but had higher growth rates during the most rapid growth period (<10 days old). The within-individual effects suggest that the higher growth rates could be due to mothers compensating (e.g. through increased food intake) for late parturition rather than by improved food availability. Date of parturition did not influence adult body size in pups. Pups became volant at the earliest only 13.1 days after birth and approached adult flight patterns during their first flight week. Our results suggest that E. nilssonii is highly adapted to a short breeding season by producing large, fast developing and early volant pups, despite the environmental pressures bats face at northern latitudes.

Long-term monitoring of a population of greater horseshoe bat emphasises the importance of a pest beetle prey on demographic trends.

The global decline in insect biomass has far-reaching implications for terrestrial and freshwater food webs, impacting species reliant on insects as a crucial component of their diet. This issue extends to species traditionally considered agricultural pests, such as the common cockchafer Melolontha melolontha. In the race to combat cockchafers through collection, insecticide use, and other control methods, the repercussions of their numerical fluctuations on predators, including species of high conservation importance like bats, have been largely overlooked. Drawing on 31-years of monitoring data for a greater horseshoe bat Rhinolophus ferrumequinum population in the Aosta Valley (Western Italian Alps), we investigated whether annual fluctuations in bat counts are influenced by cockchafer availability and weather conditions. Despite an overall positive trend in bat abundance, we observed pronounced annual fluctuations, mostly driven by cockchafer availability rather than variations in temperature and precipitation. Furthermore, we found a significant association between cockchafer availability and the median date of birth and birth rate of bats. Births occurred approximately 5 days earlier in cockchafer flight years, with earlier births also linked to warmer spring temperatures and higher numbers of warm days in April. Moreover, the ratio pups/older bats was 0.56 in cockchafer flight years, compared to 0.47 in other years. Our results underscore the importance of considering predator-prey dynamics when examining the long-term population trends of species of conservation concern. We recommend implementing restrictions on the use of chemicals and other potentially harmful practices that may diminish prey abundance or quality, including that of species considered as agricultural pests. In designing conservation strategies, a delicate balance should be struck between the current interests of farmers and the overarching goal of preserving biodiversity against potential future threats.

Study on Population and Roosting Ecology of Bats in and Around Chikkamagaluru

Bats spend over half of their lives in their roost environment, so these eventually play a prominent role in their ecology and evolution. Roosts are vital to the bats as it is plays where they actively get involved in mating, rearing offspring’s and facilitate the social living. With this background, the present study has been planned to evaluate the ecobiology of the bats in the vicinity of Chikkamagaluru. It is situated roughly in the south western part of Karnataka exists in mid-Western Ghats. The population dynamics of bat roosts were studied by emergence Count and direct roost count method. The roosting trees were identified by using standard botanical taxonomic keys. Bats roosted much more in trees belonging to Fabaceae family (1,527) followed by Myrtaceae family (1,180), Moraceae family (519), Bignoniaceae family (253), Sapindiaceae family (202), Proteaceae family (103), and very less population found in Poaceae family (21). Bat roosted much more in Pipal tree (40.72%), Red buckeye (26.03%), Banyan tree (19.97%), Rubber tree (6.18%), Avenue tree (3.22%), Bamboo (2.7%) and very less population in Tamarind tree (1.15%) in rural side of the study area. Where as in the city premises bats roosted much more in Nilgiri tree (38.19%), followed by Blue jacaranda tree (29.72%), White locust tree (25.26%) and very less roosting of bats in Silver tree (6.81%).In the present survey the population of bats and hosting trees varies from one locality to another locality. This is because of variation in vegetation, environmental condition and more or less adoptability of food and water and the less or more predators. The present study showed that bats preferred to roost in taller and larger trees having greater canopy areas as roosting sites, because these trees could provide more space for their large colonies.

Importance of Heritage Structures as Bat Roosts in the Sahara Desert

ABSTRACTIn addition to the availability of water and invertebrate prey, roost sites are considered the main factors enabling bats to survive in desert areas. Because suitable roost sites are often limiting resources, human constructions are also important for these animals. Conversely, in the context of built heritage conservation, bats are often discussed as a cause of damages. However, if historic structures deteriorate, they may lose their suitability as roosting sites for bats. This study examines how the condition of domed tombs in Sudan affects their use by bats. Inspections of 19 tombs revealed that bats occupied only undamaged structures, with 1652 individuals of four species found. Slightly and partially damaged tombs were not used by bats. These findings highlight the importance of preserving man‐made structures as critical roosting sites in arid environments to support local bat populations.

Bat Conservation Strategy In Duasudara Mountain Nature Reserve As Ecotourism Potential Of North Sulawesi, Indonesia

Sulawesi is a geologically complex island with unique fauna, including significant bat populations. This study aimed to identify bat species diversity, endemism, conservation status, and recommend conservation strategies in the Gunung Duasudara Nature Reserve. The research, conducted from May to August 2018 using mist nets across seven vegetation types, recorded 15 bat species with 475 individuals. Notable species include Acerodon celebensis, Boneia bidens, and Thoopterus nigrescens, categorized as near threatened by the IUCN. Newly discovered species M. tailiniensis, R. tangkokoensis, and T. tailiniensis exhibit distinct characteristics. The study's analyses suggest that maintaining the Nature Reserve’s status is crucial for its development as a center for education, research, and ecotourism, emphasizing the need for supportive regional policies and stakeholder involvement to ensure sustainable conservation efforts.

Diversity of bartonellae in mites (Acari: Mesostigmata: Macronyssidae and Spinturnicidae) of boreal forest bats: Association of host specificity of mites and habitat selection of hosts with vector potential.

Research into various bacterial pathogens that can be transmitted between different animals and may have zoonotic potential has led to the discovery of different strains of Bartonella sp. in bats and their associated ectoparasites. Despite their enormous species diversity, only a few studies have focussed on the detection of bacterial pathogens in insectivorous bats of boreal forests and their associated Macronyssidae and Spinturnicidae mites. We collected and molecularly analysed mite samples from forest-dwelling bat species distributed all along the boreal belt of the Palearctic, from Central Europe to Far East. Ectoparasitic mites were pooled for DNA extraction and DNA amplification polymerase chain reaction (PCRs) were conducted to detect the presence of various bacterial (Anaplasmataceae, Bartonella sp., Rickettsia sp., Mycoplasma sp.) and protozoal (Hepatozoon sp.) pathogens. Bartonella sp. DNA was detected in four different mite species (Macronyssidae: Steatonyssus periblepharus and Spinturnicidae: Spinturnix acuminata, Sp. myoti and Sp. mystacinus), with different prevalences of the targeted gene (gltA, 16-23S ribosomal RNA intergenic spacer and ftsZ). Larger pools (>5 samples pooled) were more likely to harbour Bartonella sp. DNA, than smaller ones. In addition, cave-dwelling bat hosts and host generalist mite species are more associated with Bartonella spp. presence. Spinturnicidae mites may transmit several distinct Bartonella strains, which cluster phylogenetically close to Bartonella species known to cause diseases in humans and livestock. Mites with ubiquitous presence may facilitate the long-term maintenance (and even local recurrence) of Bartonella-infestations inside local bat populations, thus acting as continuous reservoirs for Bartonella spp in bats.

Re-establishing historic ecosystem links through targeted species reintroduction: Beaver-mediated wetlands support increased bat activity

Despite the global significance of wetlands, conservation strategies often fall short in preserving these ecosystems due to failures in incorporating processes that sustain the ecosystem functioning, hydrological dynamics, ecological processes, and biodiversity of wetlands. Nature-based solutions, such as the reintroduction of beavers, have emerged as effective tools for promoting wetland restoration. Whilst the impact of beavers on wetland restoration is well known, their broader influence on ecosystem health, particularly in modifying habitats for other species, remains inadequately understood. Here we assess the impact that habitat modification through the reintroduction of beavers has on bat populations. There were significantly greater activity levels within beaver-modified wetland habitats for multiple bat species, including higher activity levels of 393 % for Barbastella barbastellus and 313 % for Plecotus spp.. Additionally, we observed positive effects on bat populations in the woodland habitat surrounding beaver-modified wetland for certain taxa. In the face of escalating challenges posed by climate change and habitat loss, addressing biodiversity loss necessitates a shift toward ecosystem-centric mitigation measures. Our study demonstrates that the reintroduction of keystone species like beavers can re-establish historical facilitative links between aquatic and terrestrial food webs, highlighting the importance of such interventions in fostering the resilience and sustainability of entire ecosystems.

Distribution and Habitat Selection of Indian Flying Fox, Pteropus medius (Temminck, 1825) in Uttar Pradesh, India

The present study examines the distribution and habitat selection of Indian flying fox, Pteropus medius in Uttar Pradesh, India. A through field work conducted across six districts revealed 22 roosting locations with a total population of approximately 12,023 bats. These sites were located at rural (12), semi-urban (2), urban (1), agricultural (5), and industrial (2) areas, and a majority of roost sites observed close to human habitations. Pteropus medius preferred to roost on 20 species of trees which indicate wide-ranging habitat preferences. Although there were considerable differences in tree attributes across different species, such as tree height (ranging from 9.54 to 26.03 meters), canopy width (varying from 8.59 to 25.09 meters), crown height (ranging from 1.19 to 18.90 meters), circumference (ranging from 0.54 to 3.65 meters), and DBH (ranging from 0.17 to 3.73 meters), and there was no notable variation in bat occupancy per roost tree. The results of the regression analysis emphasized the significance of canopy width as a predictor of colony size, indicating its importance in identifying suitable roosting habitats for P. medius. ANOVA analysis indicated differences in tree characteristics across species, highlighting the necessity for through habitat evaluations. Subsequent post-hoc examination clarified distinct clusters of tree species with significant variations in roosting site features. These results underscore the intricate relationship between tree attributes and bat populations, emphasizing the significance of well-informed conservation approaches for the sustainable preservation of P. medius and the overall ecosystem well-being.

Monitoring of Astroviruses, Brno-Hantaviruses, Coronaviruses, Influenza Viruses, Bornaviruses, Morbilliviruses, Lyssaviruses and Pestiviruses in Austrian Bats.

Here, we report the results of a monitoring study of bat viruses in Austria to strengthen the knowledge of circulating viruses in Austrian bat populations. In this study, we analyzed 618 oropharyngeal and rectal swab samples from 309 bats and 155 pooled tissue samples from dead bats. Samples were collected from 18 different bat species from multiple locations in Austria, from November 2015 to April 2018, and examined for astroviruses, bornaviruses, coronaviruses, hantaviruses, morbilliviruses, orthomyxoviruses (influenza A/C/D viruses), pestiviruses and rhabdoviruses (lyssaviruses) using molecular techniques and sequencing. Using RT-qPCR, 36 samples revealed positive or suspicious results for astroviruses, Brno-hantaviruses, and coronaviruses in nine different bat species. Further sequencing revealed correspondent sequences in five samples. In contrast, none of the tested samples was positive for influenza viruses A/C/D, bornaviruses, morbilliviruses, lyssaviruses, or pestiviruses.

Using mobile acoustic monitoring and false‐positive N‐mixture models to estimate bat abundance and population trends

AbstractEstimating the abundance of unmarked animal populations from acoustic data is challenging due to the inability to identify individuals and the need to adjust for observation biases including detectability (false negatives), species misclassification (false positives), and sampling exposure. Acoustic surveys conducted along mobile transects were designed to avoid counting individuals more than once, where raw counts are commonly treated as an index of abundance. More recently, false‐positive abundance models have been developed to estimate abundance while accounting for imperfect detection and misclassification. We adapted these methods to model summertime abundance and trends of three species of bats at multiple spatial scales using acoustic recordings collected along mobile transects by partners of the North American Bat Monitoring Program (NABat) from 2012 to 2020. This multiscale modeling spanned individual transect routes, larger NABat grid cells (10 km × 10 km), and across the entire extent of modeled species ranges. We estimated relationships between species abundances and a suite of abiotic and biotic predictors (landcover types, climatological variables, physiographic diversity, building density, and the impacts of white‐nose syndrome [WNS]) and found varying levels of support between species. We present clear evidence of substantial declines in populations of tricolored bats (Perimyotis subflavus) and little brown bats (Myotis lucifugus), declines that corresponded in space and time with the progression of WNS, a devastating disease of hibernating bats. In contrast, our analysis revealed that similar population‐wide declines probably have not occurred in big brown bats (Eptesicus fuscus), a species known to be less affected by WNS. This study provides the first abundance‐based species distribution predictions and population trends for bats in their summer ranges in North America. These models will probably be applicable to assessing wildlife populations in other monitoring programs where acoustic data are used or where false‐negative and false‐positive detections are present. Finally, our abundance framework (as a spatial point pattern process) can serve as a foundation from which more sophisticated integrated species distribution models that incorporate additional streams of monitoring data (e.g., stationary acoustics, captures) can be developed for North American bats.

A wingless fly on a winged mammal: host-parasite dynamics between Basilia travassosi (Diptera: Nycteribiidae) and Myotis lavali (Chiroptera: Vespertilionidae).

Nycteribiidae encompasses a specialized group of wingless blood-sucking flies that parasitize bats worldwide. Such relationships are frequently species- or genus-specific, indicating unique eco-evolutionary processes. However, despite this significance, comprehensive studies on the relationships of these flies with their hosts, particularly in the New World, have been scarce. Here, we provide a detailed description of the parasitological patterns of nycteribiid flies infesting a population of Myotis lavali bats in the Atlantic Forest of northeastern Brazil, considering the potential influence of biotic and abiotic factors on the establishment of nycteribiids on bat hosts. From July 2014 to June 2015, we captured 165 M. lavali bats and collected 390 Basilia travassosi flies. Notably, B. travassosi displayed a high prevalence and was the exclusive fly species parasitizing M. lavali in the surveyed area. Moreover, there was a significant predominance of female flies, indicating a female-biased pattern. The distribution pattern of the flies was aggregated; most hosts exhibited minimal or no parasitism, while a minority displayed heavy infestation. Sexually active male bats exhibited greater susceptibility to parasitism compared to their inactive counterparts, possibly due to behavioral changes during the peak reproductive period. We observed a greater prevalence and abundance of flies during the rainy season, coinciding with the peak reproductive phase of the host species. No obvious correlation was observed between the parasite load and bat body mass. Our findings shed light on the intricate dynamics of nycteribiid-bat interactions and emphasize the importance of considering various factors when exploring bat-parasite associations.

A decade of curtailment studies demonstrates a consistent and effective strategy to reduce bat fatalities at wind turbines in North America

Abstract There is a rapid, global push for wind energy installation. However, large numbers of bats are killed by turbines each year, raising concerns about the impacts of wind energy expansion on bat populations. Preventing turbine blades from spinning at low wind speeds, referred to as curtailment, is a method to reduce bat fatalities, but drawing consistent inference across studies has been challenging. We compiled publicly available studies that evaluated curtailment at six wind energy facilities in North America across 10 years. We used meta‐regression of 29 implemented treatments to determine fatality reduction efficacy as well as sources of variation influencing efficacy. We also estimated species‐specific fatality reduction for three species that comprise most fatalities in North America: hoary bat (Lasiurus cinereus), eastern red bat (Lasiurus borealis) and silver‐haired bat (Lasionycteris noctivagans). We found that curtailment reduced total bat fatalities by 33% with every 1.0 ms−1 increase in curtailment wind speed. Estimates of the efficacy for the three target species were similar (hoary bats: 28% per ms−1, 95% CI: 0.4%–48%, eastern red bats: 32% per ms−1, 95% CI: 13%–47% and silver‐haired bats: 32% per ms−1, 95% CI: 3%–53%). Across multiple facilities and years, a 5.0 ms−1 cut‐in speed was estimated to reduce total bat fatalities by an average of 62% (95% CI: 54%–69%). Mortality reductions at individual facilities in any given year were estimated to fall between 33%–79% (95% prediction interval). Inter‐annual differences rather than inter‐site or turbine characteristics accounted for most of the variation in efficacy rates. Species‐specific average mortality reduction at 5.0 ms−1 curtailment wind speed was 48% (95% CI: 24%–64%) for hoary bats, 61% (95% CI: 42%–74%) for eastern red bats and 52% (95% CI: 30%–66%) for silver‐haired bats. Practical implication. curtailment reduced bat mortality at wind turbines in this North American study. Efficacy increased proportionally as curtailment speed is raised, and patterns and rates of efficacy were similar across species. This indicates that curtailment is an effective strategy to reduce bat fatalities at wind energy facilities, but exploration of further refinements could both minimize bat mortality and maximize energy production.