Bat Activity Research Articles

Population sizes and activity patterns of little brown myotis in Yellowstone National Park

AbstractThe spread of white-nose syndrome into western North America has caused concerns that bat species inhabiting the region will soon experience population declines like those seen to the east. However, much of the region lacks baseline estimates of abundance for bats believed to be susceptible to WNS due to a scarcity of known hibernacula, where populations are traditionally monitored. The goal of this study was to determine the abundance, roost fidelity, and activity patterns of summer colonies of female little brown myotis (Myotis lucifugus) in an area with no known hibernacula. To accomplish this, we subcutaneously implanted passive integrated transponder (PIT) tags into 297 female little brown myotis from 2015 to 2018 and installed radio-frequency identification (RFID) readers and antennas inside three maternity roosts in Yellowstone National Park. Bats occupied RFID-monitored roosts on 32% of days and were never detected at maternity roosts located > 16 km from where they were tagged. Roost fidelity varied throughout summer and was greatest during late gestation and early lactation. This allowed us to combine nightly scans of RFID-tagged bats with visual emergence counts to estimate the population of bats using two roosts located >16 km apart during 2017–2018. Population estimates of both colonies were markedly higher (N* = 208 ± 6 bats and N* = 836 ± 67 bats during 2018) than the number of bats seen during evening emergence (high counts of 127 and 222, respectively). Nocturnal visits of tagged bats to these roosts increased around the time of parturition, indicative of bats returning to nurse young. These data show that emergence count and PIT tag data can be combined to monitor bat population abundance and activity patterns in areas where hibernacula are absent or where their locations are unknown.

Can citizen science provide a solution for bat friendly planning?

Urban expansion is a severe threat to biodiversity. In the UK, bats are protected meaning new developments need to be surveyed, potential impacts assessed, and appropriate mitigation action taken. However, efforts to minimise effects of urbanisation on bats are hampered by a lack of data for many species making it difficult to implement effective conservation measures. Here we explore whether citizen science data on bat activity via a passive acoustic network can be used to produce maps of high risk areas to bats from urbanisation and areas with the best opportunities for habitat mitigation. We combine the passive acoustic dataset with fine-scale habitat data and use models to quantify the effect of increasing urban areas or increasing suitable habitat (woodland, wetland, or grass and heathland). Passive acoustic detection can provide a high volume of data and large area of coverage, which is vital to the success of this modelling approach, but the data quality is dependent on accurate species classification. Therefore, we also assess the effect of identification uncertainty on the accuracy of the risk and opportunity maps. We found agreement between results accounting for species uncertainty and those that did not was high, although approximately 15% of high-risk areas would have been missed, and about 23% of habitat creation opportunities falsely prioritised. This modelling and mapping approach has great potential for use in the planning process to reduce impacts on the most important habitat features in the landscape and enable targeted habitat creation.

Spatiotemporal patterns of riparian bat assemblages in a novel riparian ecosystem

AbstractDespite increasing awareness of the ecological roles and ecosystem services that bats provide, spatiotemporal patterns in bat abundance and community assembly remain poorly understood outside of select sites in the tropics. We conducted systematic full-spectrum acoustic surveys of bats over the course of a year at eight permanent sites spanning nearly 50 km along Putah Creek, a stream in California’s Central Valley that has been subject to restoration efforts and changes to its in-stream flow regime over the past two decades. We surveyed all sites for 1 week each month. In 158 sampling nights over 11 months, we recorded 157,762 identifiable calls, thereby documenting a rich bat assemblage comprising 15 species from eight genera and two families. Seven species appeared to occur here year-round, whereas six others evidently migrated seasonally, and two were incidental visitors. Species richness and activity diversity were effectively invariant across this 50-km gradient, but assemblage composition varied both spatially and temporally. Spatial patterns suggest species-specific distributions that presumably reflect individualistic habitat preferences and responses to extrinsic factors. Species also varied temporally, with bat activity generally declining in winter, with an unexpected dip in richness and activity in late spring. For the three most commonly detected species, generalized linear models further highlighted the species-specific and individualistic nature of spatiotemporal activity patterns. When integrated with available data from other temperate sites, our results suggest that local species richness is high in temperate riparian systems. Additionally, our observations suggest that species responses to environmental variation are individualistic (e.g., “Gleasonian”) in nature and that local composition varies greatly over spatiotemporal gradients, but that emergent assemblage characteristics do not. The generality of these observations, and the underlying mechanism(s) leading to invariance in emergent characters, warrant further investigation. Similarly, the extent to which greater bat species richness provides complementary ecosystem services (hence, ecological insurance) is of both ecological and economic interest.

Can acoustic recordings of cave-exiting bats in winter estimate bat abundance in hibernacula?

Many bat species in North America face precarious futures due to white-nose syndrome and wind energy development. These threats, and others, make it imperative to monitor long-term population fluctuations of bats. Counting hibernating bats in caves estimates abundance of these cave-dwelling mammals, and such counts can be used to understand population fluctuations across time. Passive acoustic monitoring can capture large amounts of long-term data that are standardized, scalable, and reproducible; these data can also be archived for future analyses. Little work has been done, however, assessing the relationship between recorded acoustic data from bats that arouse from torpor during hibernation and fly out of caves and number of bats counted in hibernacula. We acoustically monitored and counted two species of bats in 9 hibernacula from November to March 2011 to 2018. We hypothesized that acoustic data recorded from Townsend’s big-eared bats (Corynorhinus townsendii) and western small-footed myotis (Myotis ciliolabrum) exiting hibernacula could be used to estimate abundance of those species in hibernacula. Over seven years, we conducted 29 hibernacula surveys and simultaneously set passive acoustic detectors during winter when those surveys were conducted. Acoustic monitors recorded for 1,063 nights. Detectors recorded 2,459 files of Townsend’s big-eared bats and 9,094 files of western small-footed myotis. Across all years and hibernacula, mean number of Townsend’s big-eared bats counted in a cave was 96; mean number of western small-footed myotis counted in a cave was 7. For Townsend’s big-eared bats, the top model held 43% of model weight and included the variables bat activity (i.e., mean number of Anabat files/night) and cave. For western small-footed myotis, the top model held 55% of model weight and contained the variable bat activity. Mean number of acoustic recordings of bats flying out of a cave across a winter was positively related to number of hibernating bats counted in a cave in a year for western small-footed myotis—with greater variability for estimates with a larger number of acoustic files recorded of bats flying out of caves; for Townsend’s big-eared bats that relationship held for 2 caves with > 90 individuals. Our results indicate that researchers can use passive acoustic data as an index of abundance of bats hibernating in caves in temperate climate zones. Additionally, our data indicate that researchers can acoustically detect hibernating western small-footed myotis even when these bats are not observed during hibernacula surveys. This monitoring can minimize the potential effect of researchers on the behavior of bats, facilitate long-term monitoring, and reduce the number of occasions that biologists enter caves to count bats.

Winter bat activity: The role of wetlands as food and drinking reservoirs under climate change

Bat arousals during hibernation are related to rises in environmental temperature, body water loss and increasing body heat. Therefore, bats either hibernate in cold places or migrate to areas with mild winters to find water and insects to intake. During winter, insects are relatively abundant in wetlands with mild climates when low temperatures hamper insect activity in other places.However, the role of wetlands to sustain winter bat activity has never been fully assessed. To further understand bat behaviour during hibernation, we evaluated how the weather influenced hibernating bats, assessed the temperature threshold that increased bat arousals, and discussed how winter temperatures could affect bat activity under future climate change scenarios.The effects of weather and landscape composition on winter bat activity were assessed by acoustically sampling four different habitats (wetlands, rice paddies, urban areas and salt marshes) in the Ebro Delta (Spain).Our results show one of the highest winter bat foraging activities ever reported, with significantly higher activity in wetlands and urban areas. Most importantly, we found a substantial increase in bat activity triggered when nocturnal temperatures reached ca. 11 °C. By contrasting historical weather datasets, we show that, since the 1940s, there has been an increase by ca. 1.5 °C in winter maximum temperatures and a 180% increase in the number of nights with mean temperatures above 11 °C in the Ebro Delta.Temperature trends suggest that in 60–80 years, winter months will reach average temperatures of 11 °C (except maybe in January), which suggest a potential coming interruption or disappearance of bat hibernation in coastal Mediterranean habitats. This study highlights the significant role of wetlands in bat conservation under a climate change scenario as these humid areas represent one of the few remaining winter foraging habitats.

The location and vegetation physiognomy of ecological infrastructures determine bat activity in Mediterranean floodplain landscapes

Ecological infrastructures (EI), defined as natural or semi-natural structural elements, are important to support biodiversity and could play a crucial role in counteracting the well-known impacts of intensive agriculture. Yet, the importance of EI remains largely unexplored in Mediterranean agricultural landscapes and for species providing essential ecosystem services such as bats. Here, we evaluated the role of different EI types – in terms of location (riparian vs terrestrial) and vegetation physiognomy (woody vs non-woody) – in shaping bat guild activity in crop fields located in the floodplains of the Iberian Peninsula. We recorded 60,732 bat sequences in 96 crop fields and characterised 106 EI patches via an adaptation of the Biodiversity Potential Index (BPI). We found that the activity of mid-range echolocators (MRE) and long-range echolocators (LRE) was twofold higher when the nearest EI patch was riparian (i.e., contiguous to a watercourse) than when it was terrestrial. When assessing changes in bat activity in crop fields in relation to a gradient distance from EI types, our results revealed both distinct and similar effects of the location and vegetation physiognomy of the EI on bat guilds. For instance, while only the LRE guild positively responded to the proximity of woody EI, both MRE and LRE showed a marked increase of activity when increasing distances to non-woody EI, thus suggesting low bat activity levels near these features. Our habitat quality assessment also revealed that woody EI and riparian EI had higher biodiversity potential and related habitat quality, thus contributing to our understanding of bat responses to EI type in crop fields. As riparian areas are rarely targeted in biodiversity-friendly measures in farmland, we strongly recommend including riparian EI (especially the woody type) in conservation planning as they are crucial for both biodiversity conservation and ecosystem functioning.

Кажани техногенних ділянок південно-східної України

The results of the study of bat groups in anthropogenic landscapes of the Donbass are presented. The study is a pioneer for this type of sites and can serve as a starting point for further monitoring. A total of 15 sites were surveyed using an ultrasonic detector, which allowed recording the hunting activity of bats. The frequency of registrations of bats was insignificant. Three species were identified, in particular Pipistrellus kuhlii (149), Eptesicus serotinus (39), and Nyctalus noctula (6). It is shown that there are actually only two species—Pipistrellus kuhlii and Eptesicus serotinus—in the surveyed types of landscapes, which are synanthropic and are considered alien to the region’s fauna.

Effects of lunar phase and temperature on bat activity and species richness at varying altitudes in the Kunene Region, Namibia

AbstractBat activity and species richness patterns are often used to assess bat population trends. Understanding how environmental conditions affect bat activity is thus important for bat conservation, but understudied across much of Africa. To address this information gap, we examined the effects of environmental factors (i.e. lunar phase and ambient temperature) on bat activity and species richness in the northern Namib Desert, Namibia. From May 2016 to March 2017, we deployed long‐term acoustic detectors at three locations of varying altitudes to record bat activity and captured bats to confirm species identities once per month. In total, we recorded 5865 passes from six bat families, with Vespertilionidae and Molossidae occurring at all sites. Lunar phase did not significantly affect activity on full moon versus new moon nights. Bat activity generally peaked at all sites in the early evenings independent of lunar phase, suggesting that foraging just after sunset may be adaptive. Ambient temperature had a negative effect on bat activity at all sites and bats were not active when temperatures were >35°C or ≤11°C, but bat activity peaked during the summer months. Despite differences in temperatures across sites, community composition was not related to altitude. Long‐term monitoring of desert bat activity and species richness is important not only for addressing large knowledge gaps about the population trends and behaviours of these Namibian species and about bats in arid landscapes more generally, but also for informing local bat conservation efforts across a range of environmental conditions.

Linking activity of common pipistrelles, Pipistrellus pipistrellus, in an urbanised area with a nearby mass swarming site

The Erňa cave, a mass winter hibernaculum and important swarming site of the common pipistrelle, Pipistrellus pipistrellus, is located in the Slovak Karst, near the Košice urban agglomeration in eastern Slovakia. Over the past two decades, the so-called invasions of this species have been observed in buildings in Košice. This unusual behaviour occurs in late summer or autumn and it is characterized by numerous accidental or unforeseen occurrences of bats in various spaces of these houses. It has been hypothesised that these events are related to bats swarming and hibernating in the Erňa cave; however, causality has not been confirmed. We measured the relative activity of bats from the end of the breeding season through the invasions and autumn swarming prior to the onset of hibernation by recording their echolocation calls on car-based transects in order to find any spatial and temporal linkage between activity in the urban area and the swarming site. Over two years we recorded 6,253 sequences with echolocation calls of P. pipistrellus and 5,239 records of other bats along four transects totalling 7,121 km in length. Spatial pattern analysis found that the city agglomeration presented a local hotspot of the species’ activity, especially during the invasion season. Multivariate generalised additive modelling confirmed an increased density of records of P. pipistrellus between the urban area and the hibernaculum in the pre-hibernation season, whereas this pattern was not found to be consistent on the control transects near the city. Contrary to that, other bat species showed little variation in their activity between transects and seasons. The obtained results suggest that the relatively short geographical distance between the urban agglomeration and the large swarming site is likely a clue to the frequent city invasions of the species, although the role of the city as a hibernation area cannot be completely omitted.

Contrasting Effects of Chronic Anthropogenic Disturbance on Activity and Species Richness of Insectivorous Bats in Neotropical Dry Forest

For prioritizing conservation actions, it is vital to understand how ecologically diverse species respond to environmental change caused by human activity. This is particularly necessary considering that chronic human disturbance is a threat to biodiversity worldwide. Depending on how species tolerate and adapt to such disturbance, ecological integrity and ecosystem services will be more or less affected. Bats are a species-rich and functionally diverse group, with important roles in ecosystems, and are therefore recognized as a good model group for assessing the impact of environmental change. Their populations have decreased in several regions, especially in the tropics, and are threatened by increasing human disturbance. Using passive acoustic monitoring, we assessed how the species-rich aerial insectivorous bats—essential for insect suppression services—respond to chronic human disturbance in the Caatinga dry forests of Brazil, an area potentially harboring ca. 100 bat species (nearly 50% are insectivorous), but with > 60% its area composed of anthropogenic ecosystems under chronic pressure. Acoustic data for bat activity was collected at research sites with varying amounts of chronic human disturbance (e.g., livestock grazing and firewood gathering). The intensity of the disturbance is indicated by the global multi-metric CAD index (GMDI). Using Animal Sound Identifier (ASI) software, we identified 18 different bat taxon units. Using Hierarchical Modeling of Species Communities (HMSC), we found trends in the association of the disturbance gradient with species richness and bat activity: species richness was higher at sites with higher human disturbance, whereas bat activity decreased with increasing human disturbance. Additionally, we observed taxon-specific responses to human disturbance. We conclude that the effects of chronic anthropogenic disturbance on the insectivorous bat fauna in the Caatinga are not homogeneous and a species-specific approach is necessary when assessing the responses of local bats to human disturbances in tropical dry forests, and in other biomes under human pressure.

Miniaturization eliminates detectable impacts of drones on bat activity

Abstract Advances in operational simplicity and cost efficiency have promoted the rapid integration of unoccupied aerial vehicles (UAVs) into ecological research, yet UAVs often disturb wildlife, potentially biasing measurements. Studies of UAV effects on wildlife to date have focused on UAV trajectory or distance; however, UAV size and noise could be critical variables influencing wildlife responses. Bats are cryptic aerial species that are difficult to survey using conventional means, and so we tested the effectiveness of drone‐based acoustic surveys for bats. We recorded the number of acoustic bat detections with and without a UAV present. We used three small, commercial rotary UAVs varying in size and noise intensity (249, 907, 1,380 g). Larger and louder UAVs deterred significantly more bats, with no effect of take‐off distance on bat activity. The smallest and quietest UAV model had a similar change in bat activity compared with control measurements. Drone noise increased with drone size, but all drones emitted in a similar range of frequencies that overlapped with the larger bat species that were also those most impacted by the UAV. During the 5‐minute surveys, there was no evidence of bat habituation to UAVs although bats returned quickly once the UAV survey ended. We urge wildlife researchers to consider drone size during wildlife surveys. Smaller and quieter models have negligible impacts on wildlife, eliminating the impact of drones on wildlife in some cases.

Tree size, microhabitat diversity and landscape structure determine the value of isolated trees for bats in farmland

Isolated trees are increasingly recognised as playing a vital role in supporting biodiversity in agricultural landscapes, yet their occurrence has declined substantially in recent decades. Most bats in Europe are tree-dependent species that rely on woody elements in order to persist in farmlands. However, isolated trees are rarely considered in conservation programs and landscape planning. Further investigations are therefore urgently required to identify which trees – based on both their intrinsic characteristics and their location in the landscape – are particularly important for bats. We acoustically surveyed 57 isolated trees for bats to determine the relative and interactive effects of size, tree-related microhabitat (TreM) diversity and surrounding landscape context on bat activity. Tall trees with large diameter at breast height and crown area positively influenced the activity of Pipistrellus pipistrellus and small Myotis bats (Myotis spp.) while smaller and thinner trees favoured M. myotis activity. The diversity of TreMs that can be used as roosts had a positive effect on (i) Barbastella barbastellus activity only when trees were relatively close (<50 m) to woody patches, (ii) Pipistrellus nathusii/kuhlii activity only in the most heterogeneous landscapes, and (iii) Myotis spp. activity only in the most forested environment (>10% within 100 radius scale). The potential benefits of isolated trees for bats result from ecological mechanisms operating at both tree and landscape scales, underlining the crucial need for implementing a multi-scale approach in conservation programs. Maintaining the largest and most TreM-diversified trees located in the most heterogeneous agricultural landscapes will provide the greatest benefits.

How the bat brain detects novel sounds (commentary on Wetekam et al., 2021).

How the bat brain detects novel sounds (commentary on Wetekam et al., 2021).

An Updated Review of Hypotheses Regarding Bat Attraction to Wind Turbines.

Simple SummaryThe rapid development of wind energy facilities has increased bat mortality due to wind turbine blade strikes. Patterns of bat activity and mortality at wind energy facilities suggest that bats are attracted to wind turbines. It has been more than a decade since a comprehensive review of the various attraction hypotheses was published, highlighting the need to revisit and assess progress in the testing of these ideas. In this review, we discuss the most prominent attraction hypotheses, summarize the current state of knowledge, and briefly outline remaining questions. Identifying the causes of bat interactions with wind turbines is critical to developing effective impact minimization strategies. Patterns of bat activity and mortalities at wind energy facilities suggest that bats are attracted to wind turbines based on bat behavioral responses to wind turbines. For example, current monitoring efforts suggest that bat activity increases post-wind turbine construction, with bats making multiple passes near wind turbines. We separated the attraction hypothesis into five previously proposed explanations of bat interactions at or near wind turbines, including attraction based on noise, roost sites, foraging and water, mating behavior, and lights, and one new hypothesis regarding olfaction, and provide a state of the knowledge in 2022. Our review indicates that future research should prioritize attraction based on social behaviors, such as mating and scent-marking, as this aspect of the attraction hypothesis has many postulates and remains the most unclear. Relatively more data regarding attraction to wind turbines based on lighting and noise emission exist, and these data indicate that these are unlikely attractants. Analyzing attraction at the species-level should be prioritized because of differences in foraging, flight, and social behavior among bat species. Lastly, research assessing bat attraction at various scales, such as the turbine or facility scale, is lacking, which could provide important insights for both wind turbine siting decisions and bat mortality minimization strategies. Identifying the causes of bat interactions with wind turbines is critical for developing effective impact minimization strategies.

Hawaiian hoary bat responses to habitat, season, and non‐native insectivore suppression

AbstractHabitat loss and non‐native species are 2 of the most important factors that influence native species persistence and behaviors globally. The insectivorous Hawaiian hoary bat (Lasiurus semotus) is the only extant terrestrial mammal native to the Hawaiian Islands. Non‐native invasive insectivore species, which are potential competitors of bats for prey, may influence hoary bat behavior. The goal of this study was to determine how small‐scale suppression of invasive insectivores (rodents, ants, and yellowjacket wasps [Vespula pensylvanica]) influenced bat activity in grasslands and woodlands. We measured bat activity as a function of the number of distinct minutes in a night containing bat echolocations (bat call minutes) at 20 experimental plots (each 2.25 ha) in a dryland ecosystem on Hawaiʻi Island, November 2016–January 2018. We included 3 predictor variables: vegetation type (woodland, grassland), season (bat reproductive cycle periods: lactation, mating, pre‐pregnancy, and pregnancy), and insectivore treatment type (ant suppressed, yellowjacket wasp suppressed, rodent suppressed, combined ant+wasp+rodent suppressed, and no treatment). Bat activity was associated with all 3 predictors using a negative binomial generalized linear model. Bat call minutes and feeding buzzes were twice as high in woodlands than in the grasslands (2.4 and 2.3 times as high, respectively). Bat activity was slightly lower (0.47 bat call min/night fewer) in plots receiving the combined ant + wasp + rodent treatment compared to all other treatment plots. Feeding buzzes did not differ significantly among treatments. Mean activity was lowest during lactation (mid‐Jun–Aug). Although woodlands appear particularly important for the Hawaiian hoary bat, small‐scale bat activity and foraging do not appear to be strongly affected by resource competition with the invasive insectivores in this study.

Liraglutide Activates Type 2 Deiodinase and Enhances β3-Adrenergic-Induced Thermogenesis in Mouse Adipose Tissue.

AimsLiraglutide is a long-acting glucagon-like peptide 1 (GLP-1) receptor agonist used as an anti-hyperglycemic agent in type 2 diabetes treatment and recently approved for obesity management. Weight loss is attributed to appetite suppression, but therapy may also increase energy expenditure. To further investigate the effect of GLP-1 signaling in thermogenic fat, we assessed adipose tissue oxygen consumption and type 2 deiodinase (D2) activity in mice treated with liraglutide, both basally and after β3-adrenergic treatment.MethodsMale C57BL/6J mice were randomly assigned to receive liraglutide (400 μg/kg, n=12) or vehicle (n=12). After 16 days, mice in each group were co-treated with the selective β3-adrenergic agonist CL316,243 (1 mg/kg, n=6) or vehicle (n=6) for 5 days. Adipose tissue depots were assessed for gene and protein expression, oxygen consumption, and D2 activity.ResultsLiraglutide increased interscapular brown adipose tissue (iBAT) oxygen consumption and enhanced β3-adrenergic-induced oxygen consumption in iBAT and inguinal white adipose tissue (ingWAT). These effects were accompanied by upregulation of UCP-1 protein levels in iBAT and ingWAT. Notably, liraglutide increased D2 activity without significantly upregulating its mRNA levels in iBAT and exhibited additive effects to β3-adrenergic stimulation in inducing D2 activity in ingWAT.ConclusionsLiraglutide exhibits additive effects to those of β3-adrenergic stimulation in thermogenic fat and increases D2 activity in BAT, implying that it may activate this adipose tissue depot by increasing intracellular thyroid activation, adding to the currently known mechanisms of GLP-1A-induced weight loss.

One size doesn’t fit all: Singularities in bat species richness and activity patterns in wind-energy complexes in Brazil and implications for environmental assessment

Wind energy is an important electricity source. Even though it is cleaner than other energy sources in terms of greenhouse gas emissions, gathering energy from the wind has impact on organisms that fly, including bats. Understanding whether and how bat activity patterns are affected by environmental variables may be useful when trying to mitigate these impacts, for example bat mortality from collisions with wind turbines. Northeastern Brazil concentrates one of the world’s largest wind potentials and has thousands of wind turbines in operation. In spite of this scenario, there is a lack of basic information, such as the presence of bat species and their activity patterns in those wind farms. We used passive acoustic monitoring to assess species richness and species composition and obtain data on activity patterns of insectivorous bats in four wind farm complexes in northeastern Brazil. We also investigated the possible correlation between environmental variables (wind speed and direction, air temperature and humidity, and percentage of moon illumination) and bat activity. The acoustic monitoring carried out for 30 nights produced approximately 120,000 bat passes of 29 sonotypes and four families. Environmental variables may influence bat activity, but in a site-specific way, i.e., although the environmental conditions of wind-energy complexes were similar, there was not an activity pattern common to all. Considering such specificities, we strongly recommend long-term specific on-site monitoring in each wind complex, avoiding generalizations for the environmental licensing of wind energy in Brazil.

Eclipsed: Emergence-return activity of two pteropodid bat species during lunar eclipse

Lunar eclipses are known to influence flight activity of tropical bats at foraging sites. However, little is known about the onset and offset of flight activity from the roost during lunar eclipses compared to other full moon nights. Emergence from and return to the roost were observed during a total lunar eclipse at a colony of the fruit bat Rousettus leschenaultii and during a partial lunar eclipse at a Pteropus giganteus colony in southern India. In addition, on the same partial eclipse night, a single male P. giganteus was tracked using GPS telemetry. Flight activity in both species was compared between the eclipse night and other full moon nights. In both cases, bats emerged before the eclipse and fewer R. leschenaultii individuals returned to the roost during the hours of the total eclipse, compared to the corresponding hours during other full moon nights. No such difference in return activity was observed in the P. giganteus colony or in the GPS tracked individual between the partial eclipse and other nights. This is the first attempt to study temporal flight activity of bats during lunar eclipses at their roosting sites. More roosting site observations, especially on species that roost in the open, are required to understand the effects of lunar eclipses on bat activity.

The influence of small wind turbines on bat activity in Eastern Hokkaido

The influence of small wind turbines on bat activity in Eastern Hokkaido

Fauna and flight activity of bats in natural forests in the southern Brdy Mts. and the first information on the occurrence of Hypsugo savii in this area (Chiroptera: Vespertilionidae)

The bat fauna was studied at six localities of protected natural forest fragments in the southern part of the Brdy Mts. (south-western Bohemia), in the years 2019–2020. Netting and acoustic detection on line transects were used in order to document the species composition and flight activity of bats at the localities under study. Altogether, 24 individuals of seven bat species were netted. In total, 643 minutes of the presence of flying bats were registered within 56.5 transect hours. With use of these methods, at least 16 bat species were recorded. Of them, Myotis myotis, M. mystacinus / M. brandtii, M. nattereri, Eptesicus nilssonii, Pipistrellus pipistrellus, Plecotus auritus, and Barbastella barbastellus represent the constant species group with respect to their occurrence at the localities. Pipistrellus pipistrellus was the most frequent species (54%), with the highest relative flight activity at all localities. The highest intensity of flight activity of the bat community was observed in habitats with rocks, boulder accumulation, and open stony debris (14.17 min+/h). The highest bat species diversity was registered in habitats with the prevalence of herb-rich mixed beech forest stands (15 species, diversity index H’=2.02; equitability E=0.75). A series of calls of Hypsugo savii was registered in the Na skalách Nature Reserve on 8 May 2020. It represents the first finding of this species in the region of the Brdy Mts.