Bat Fauna Research Articles

Reducing bat mortality at wind farms using site-specific mitigation measures: a case study in the Mediterranean region, Croatia

Abstract A 4-year monitoring of bat fauna at Rudine wind farm in Croatia aimed to produce mitigation measures to minimize both the number of bat fatalities and power loss in energy production. During the first 2 years, a high number of carcasses was found from mid-July to the end of October, indicating the need for some mitigation strategy. Based on the results of carcass searches, meteorological data and bat activity monitored at a weather mast and four wind turbine nacelles, mitigation measures were proposed. During the next 2 years, wind turbine curtailment was implemented in the high collision risk period based on critical wind speed thresholds varying from 5.0 to 6.5 ms−1. Estimation of a total number of bat fatalities was conducted with the GenEst software for each monitoring year. A 78% reduction in estimated number of fatalities was recorded indicating the effectiveness of implemented measures.

Important underground roosts for bats in Bulgaria: current state and priorities for conservation.

Bulgaria has a very rich bat fauna and large colonies of bats can be found in caves, mines and other underground roosts. Respectively, there are more than 107 underground roosts that are listed as important bat sites, most of which are protected by statutory laws and are of national or international importance. Despite the existence of formal protection, many roosts face anthropogenic disturbances due to the popularity of outdoor activities, such as caving and the lack of actual regulation. Currently, the evaluation was only based on the size of the colony and the presence of protected species. However, this approach is limited to roosts that contain high diversity and neglects the ones that contain high biotic importance that are highly threatened by various threats. Here, we evaluated conservation priorities and identified the most vulnerable underground bat roosts in Bulgaria, using the Bat Cave Vulnerability Index and proposed measures to adequately protect sites. We found that 32% of the Bulgarian bat roosts assessed are at a "high priority" level for conservation and protection, while 39% are at a "medium priority" that may require constant monitoring. This novel and integrative approach applied to bat roost prioritisation in the country enabled the detection of sites that need urgent conservation attention and is the first step in establishing better strategies for the bat monitoring network in Bulgaria.

A review of bats of the genus Pseudoromicia (Chiroptera: Vespertilionidae) with the description of a new species

The Cameroon Volcanic Line, which divides the Congo Basin fauna from the West African fauna, is a known area of high endemism for various taxa, but the region’s bat fauna has received little attention. We review variation in morphological and molecular (mitochondrial Cytochrome b) characters in the Tropical African vespertilionid bat genus Pseudoromicia. Assessment of this variation indicates the existence of a new species of Pseudoromicia, from the Mbam Minkom Massif in the Centre Region of Cameroon. The new species is diagnosable by sequence data and is morphologically similar to its putative sister taxon, P. kityoi, from Uganda. Although we suggest that it be assigned to the IUCN category of Data Deficient, there should be some concern as to the conservation status of this species: the Mbam Minkom Massif ecosystem is threatened due to lack of legal conservation frameworks and exposure to increasing human pressure. The new species is in a clade with P. roseveari and P. kityoi. These three species may be relicts of a single widespread species originating in the West African “white-winged” group of Pseudoromicia that then spread east across the tropical moist broadleaf forest into East Africa, and are now restricted to a few upland rainforest patches in West Africa (P. roseveari), in outliers of the Cameroon Volcanic Line region (Pseudoromicia sp.), and the Lake Victoria area (P. kityoi). The smaller, white-winged species are hypothesized to be ancestral, with one extant putative species (P. rendalli) also extending into East and southern Africa (Van Cakenberghe & Happold, 2013). The larger, dark-winged taxa likely dispersed to East Africa and subsequently back to West Africa (e.g., Pseudoromicia sp., P. roseveari). Our data illustrate the potential importance of the Dahomey Gap and climatic changes in the evolution of this group of species. http://zoobank.org/urn:lsid:zoobank.org:pub:30929BAA-4043-422D-B209-16CAB826043E

Differences in the structure of bat assemblages among habitats in the Caatinga dry forest

Abstract The Caatinga is the largest seasonal tropical dry forest with extreme environmental and meteorological conditions. It harbours many phytophysiognomies and vegetational units, but bat fauna is poorly known in many regions. We analysed the structure of bat assemblages by mist-netting during 99 nights in seven habitats throughout six sites in the northeasternmost region of the Caatinga in Rio Grande do Norte State, in the Brazilian northeast. With a sampling effort of 239 665 m2h, we captured 1575 individuals of 31 species of bats. Bat assemblages’ structure and species distribution changed according to the habitat type, and differences in richness, abundance, species composition, and trophic guild representation were found. The frugivore A. planirostris was widespread, and its superabundance hold for all habitats. The distinct array of the most abundant species with several exclusive species in each habitat suggests species- and trophic guild-specific preferences to particular habitats. Differences in the structure of bat assemblages may be driven by each habitat’s vegetational structure and plant composition (e.g., semi-open habitats vs. tall forest stands) that offers distinct exploitable resources (e.g., food and roosts). Finally, we discuss the importance of foraging habitats for the conservation of these unique bat assemblages in the northeasternmost region of the Caatinga dry forest.

ПЕРВАЯ НАХОДКА NYCTALUS LEISLERI (KUHL, 1817) (CHIROPTERA, VESPERTILIONIDAE) В МОРДОВСКОМ ГОСУДАРСТВЕННОМ ЗАПОВЕДНИКЕ (ЕВРОПЕЙСКАЯ РОССИЯ)

Nowadays, the fauna of bats of protected areas in the Republic of Mordovia is poorly studied. We have investigated the species composition and abundance of bats in the Mordovia Nature Reserve in JulyAugust 2021, 2022. In total, 986 individuals of 10 bat species were caught. The habitation in the reserve of nine bat species previously known were confi rmed. For the fi rst time, the habitation of a new species in the nature reserve, the lesser noctule Nyctalus leisleri (Kuhl, 1817) (Chiroptera, Vespertilionidae), was revealed. The results of counts of bat fauna in the Mordovia Nature Reserve are presented.

BatMap – authoritative distribution maps for Australian bats

BatMap is a project that has enabled the development of spatial distribution maps for all mainland Australian and Tasmanian bat species. The distribution maps were developed by bat experts and are actively updated and maintained by utilising the collective knowledge of the members of the Australasian Bat Society. Distribution maps are the most accurate maps that are currently available for Australian bat species. The distribution maps are freely available on-line in a variety of formats. The distribution maps have been used for a variety of purposes, including the assessment of the spatial and taxonomic accuracy of bat records from ecological datasets, particularly datasets that are managed by the Atlas of Living Australia, which are considered by many to be the key source of spatial information for bats. BatMap enables better conservation outcomes for Australian bat fauna through the provision of authoritative, readily accessible and usable maps that can be used to increase the accuracy and reliability of bat records that contribute to decision making processes for conservation purposes.

Кажани Галичини та Буковини 1830–1850 років: склад і зміни фауни за 180 років

The chiropterological component of one of the most significant zoological written monuments of the 19th century of Ukraine in general and the Carpathian region in particular is analysed. This is Stanislaw Petruski’s monograph titled ‘Natural History of Wild Mammals of Galicia’ (1853). The translation of this part has been arranged and commented in accordance with modern schemes of bat taxonomy and nomenclature supplemented with appropriate descriptions from the works of Alexander Zawadski (1840) and Ivan Verkhratsky (1869). Consequently, the most complete picture of the species composition and some features of the biolo-gy of the bat fauna of Prykarpattia (essentially the Carpathian region on the whole) within Ukraine was reconstructed and described, which is important for understanding the composition of past fauna states in neighbouring countries, including Poland and Romania. Descriptions of 12 species from 9 genera are presented and commented taking into account the current state of knowledge. The underestimation concerned only rare species and those morphologically simi-lar to other more common ones (e.g. lesser horseshoe bat, Brandt’s bat, Nathusi-us’s pipistrelle, lesser noctule, etc.). Features of contemporary taxonomy, fauna composition, descriptions of dwellings and display of synanthropy are considered. Special attention is paid to the consideration of fauna changes that have occurred over almost 100 years, as well as the features of the fauna of that time, which shows obvious signs of the ‘warm phase.’ The latter is evidenced by descriptions of species in the fauna in general, which are currently more southern, and descrip-tions of winter finds of those species that in the last period of research (second half of the 20th century) were considered migratory and distant migrants. The main body of data by Petrusky, as follows from his text, dates from 1830–1850, and this corresponds to the period of climatic optimum reconstructed for Poland, where the period 1820–1850 was characterised by warm late winters and early springs. Apparently, the same period extended to Galicia, and later descriptions of ‘warm fauna’ in Ukraine are known for the period of the 1920–1930s and the modern period (1990–2020). The phenomenon of constant cycle of fauna and its regular changes due to climate fluctuations is considered.

Bats (Mammalia, Chiroptera) and bat flies (Diptera, Streblidae) from the Cazumbá-Iracema and Chico Mendes Reserve, Western Brazilian Amazon.

Bats belong to the order Chiroptera and are composed of 18 families, 202 genera, and 1420 species. Cosmopolitans, they have a high diversity of trophic and behavioral guilds, several ecosystem services, and intraspecific associations with ectoparasites. In Brazil, 68 species of Streblidae have already been recorded, although knowledge about the bat fauna and their ectoparasites is still low. Thus, the objective was to present a list of bat species, and to relate parasites with hosts, for two extractive reserves in the state of Acre, western Brazilian Amazon. The collections took place in ten nights, five in each RESEX, both carried out in August 2019. At each point, 10 mist nets (9m × 2.5m) were used, remaining open for 6h. The captured bats were stored in cotton bags and had their data collected. Subsequently, the search for ectoparasites was carried out throughout the individual's body and extracted with brushes moistened with 96% ethyl alcohol and fine-tipped tweezers. Species of flies were identified to the lowest taxonomic level through specific bibliography. Thirty-three bats from six trophic guilds and 46 ectoparasitic dipterans were sampled, all from the Streblidae family. The most abundant bat family was Phyllostomidae, a recurring result in several studies carried out in the neotropical region. This is related to the selectivity of the mist net in bat sampling, in addition to a close correlation between Phyllostomidae bats and ectoparasitic flies of the Streblidae family.

Assessment of Seasonal Variability of the Spectrum of Free Amino Acids in the Blood Plasma of the Boreal Bat Species (Myotis dasycneme Boie, 1825) of the Ural Fauna

A comparative analysis of the content of free amino acids in the blood plasma of a representative of the bat fauna of the Urals, Myotis dasycneme (Boie, 1825), in seasonal periods of their annual life cycle is presented for the first time. The blood plasma of the pond bats contains a full spectrum of essential amino acids: threonine, valine, lysine, leucine, isoleucine, methionine, phenylalanine, arginine, histidine, and tryptophan. A significant accumulation of metabolically active glucoplastic alanine in the blood of M. dasycneme in the autumn (2.5 times) and winter (2.2 times) periods indicates its role as a low-temperature adaptogen.

Trophic structure and foraging strategies in a bat community in northern Pantanal, Brazil

Abstract The influence of the landscape mosaic on the composition of the bat fauna regarding its trophic guild in a ranch area of northern Pantanal was evaluated. Seven trophic categories and five foraging strategies were found, composing 11 guild associations. Cluster analysis and non-metric multidimensional scaling (NMDS) revealed the structure of the data and enabled a broader understanding of resource exploitation. The similarity between sites for the presence of guilds was moderate, with the presence of aerial insectivores and trawling insectivores occurring in most of them, mainly in pasture areas and in the cambará forest. Gleaning sedentary frugivores, gleaning nomadic frugivores, and gleaning nectarivores were present in almost all sites, most often in dense acuri palm forest. Frugivores were the most numerous at the individual level, followed by trawling insectivores and hematophagous. The similarities between groups ranged from low to moderate. Some subgroups identified in the analyzes showed high similarity, with strong congruences between sites. The areas used by cattle do not seem to restrict the use by some species of bats, especially those already proven to be associated with degraded areas. However, information is still lacking to predict which level of alteration is acceptable for the conservation of each guild and foraging strategy of bat species.

Extensive gene flow in a threatened bat (Rhinonicteris aurantia) in an arid landscape

The bat fauna of Australia comprises some 25% of all terrestrial species, yet we know very little of the demography, dispersal, and movement dynamics of most bat species. The Pilbara leaf-nosed bat ( Rhinonicteris aurantia Pilbara form) is a threatened microbat that roosts exclusively in caves that occur in mineral rich deposits in the Pilbara region. Due to their specific roost microclimate requirements these bats cannot survive for long without a suitable roost and are sensitive to roost disturbance. Understanding the connectivity of roosts throughout the Pilbara is crucial for informed decisions to mitigate potential impacts to persistence of this species in areas under economic development. Along with mitochondrial DNA (mtDNA) markers, we used reduced representation genomic sequencing of over 150 individuals from eight roost sites throughout the Pilbara and tested for landscape-scale population differentiation associated with the two major subregions — the Hamersley and Chichester, as well as finer-scale among roost variation. We found evidence of high rates of dispersal and low population structure within the Pilbara, indicating one panmictic population, with mtDNA results suggesting evidence of some female philopatry. Our results highlight the ongoing need for detailed genetic studies to provide critical insight to species dispersal, particularly in multi-use landscapes. We discuss the importance of identifying and retaining connectivity of key habitat to maintain genetic diversity and gene flow throughout panmictic populations.

New records of Nyctalus leisleri (Kuhl, 1817) and Myotis nattereri (Kuhl, 1817) (Mammalia: Chiroptera: Vespertilionidae) from National Park “Smolny” and its surroundings, Republic of Mordovia

Protected areas in the Republic of Mordovia are still poorly studied in relation to bats. Our research of the bat fauna in the National Park “Smolny”, Republic of Mordovia was conducted in 2018‒2020. A total of 573 bats of nine species belonging to the family Vespertilionidae were captured and studied. Nyctalus leisleri and Myotis nattereri were caught here for the first time. Three new sites of two rare bat species were discovered. The list of bats in the National Park “Smolny” currently includes 10 species.

Karstic Limestone Outcrops Harbor High Bat Diversity in a Deeply Anthropized Landscape in Southeastern Brazil

The availability of shelter in karst areas affects the richness, abundance, and assemblage composition of bat species and may play an important role in movement dynamics, activity patterns, and foraging behavior. Our work in the midwestern region in the state of Minas Gerais, southeastern Brazil, showed a high richness of the bat fauna, given the anthropic impact caused by mineral exploration and agricultural activities, thus leaving vegetation islands over karst areas in a vast anthropized matrix. Sampling at 12 sites resulted in 1,444 captures of bats, representing 30 species. Our beta diversity partitioning analyses indicated a pattern of turnover, i.e. species replacement, suggesting that these vegetation fragments may function as ecological springboards or stopping points.

A New Species of Horseshoe Bat (Chiroptera: Rhinolophidae) from Mount Namuli, Mozambique

The ecology of the high-altitude mountains of northern Mozambique is understudied in comparison to surrounding countries. A series of biological surveys have focused on filling this data gap, with Mount Namuli in Zambezia Province one of the focal sites of these expeditions. A biological survey of Mount Namuli in 2009 resulted in the collection of five specimens of a horseshoe bat species (Rhinolophidae) that is here described as a new species from Mozambique. Morphologically, the new species is very similar to Rhinolophus maendeleo Kock, Csorba and Howell, 2000 of the adami-group, but lacks some key morphological characters of this group (large ears, narrow skull, long palate). Molecular reconstructions clearly suggest the new species belongs to the capensis-group, but no members of the adami-group were included in this analysis (due to lacking data). It is thus unclear whether this unexpected phylogenetic position reflects morphological convergences between members of the adami- and capensis-groups, or whether the morphology-based adami-group should be reconsidered. The new species and R. maendeleo share similar external and craniodental measurements, but can be distinguished based on a number of key characters. These include the presence of a bony bar forming the interorbital foramena, rostrum shape, ear length and highly differing bacular morphologies. It also differs from the genetically closely related R. denti Thomas, 1904, R. swinnyi Gough, 1908 (including two recently described cryptic species) and R. simulator Andersen, 1904 by non-overlapping external and cranial measurements. The new species echolocates at a mean peak frequency of 76.9 kHz and shows an affinity to forest habitats, which are highly threatened in the surrounding region. It joins other coastal and montane forest endemics in defining the bat fauna of south-eastern Africa.

Phylogenetic relationships of Ochoterenatrema Caballero, 1943 (Digenea: Lecithodendriidae) with descriptions of two new species.

Ochoterenatrema is a small genus of lecithodendriid digeneans that includes six species parasitic in Neotropical bats in North and South America. Members of this genus are characterized by the presence of a pseudogonotyl formed by thickened tegument on the left side of the ventral sucker. We examined morphology of specimens belonging to five species of Ochoterenatrema from Brazil, Ecuador and the USA and describe two new Ochoterenatrema spp. (Ochoterenatrema sphaerula n. sp. and Ochoterenatrema gracilis n. sp.). These new species are readily differentiated from their congeners by a combination of morphological characters, including the distribution of vitelline follicles and the body shape. We have provided the first DNA sequences for Ochoterenatrema. Newly generated partial nuclear 28S rDNA and mitochondrial cox1 gene sequences were used to differentiate among species and study the phylogenetic affinities of Ochoterenatrema spp., including one of the new species, O. gracilis n. sp., as well as Ochoterenatrema diminutum, Ochoterenatrema fraternum and Ochoterenatrema cf. labda. The phylogeny of the Microphalloidea based on 28S had well-supported topology, particularly at the family level. The Ochoterenatrema clade was strongly supported; however, the internal topology of the clade was weakly supported. Comparison of sequences revealed 0.4-1.3% interspecific divergence in 28S and 9.1-19.7% interspecific divergence in cox1 among Ochoterenatrema spp. We hypothesize that extremely diverse fauna of bats in South and Central America harbors multiple undescribed species of Ochoterenatrema. Several lecithodendriid genera from bats and other hosts are yet to be included in future molecular phylogenetic analyses to test the monophyly of this extremely diverse digenean family and analyze evolutionary affinities of its constituent taxa.

NEW RECORDS ABOUT THE DIVERSITY, DISTRIBUTION, AND SEASONAL ACTIVITY PATTERNS BY BATS IN YUKON AND NORTHWESTERN BRITISH COLUMBIA

The bat fauna of northwestern Canada remains poorly known, principally owing to a lack of dedicated surveys across this vast region. To better assess the diversity of bats in the region, we compiled records from several acoustic survey projects and capture sessions whose purpose was to inventory bats in Yukon and northwestern British Columbia (BC) from 2013 to 2018. During our surveys we obtained the 1st apparent acoustic records for Yuma Myotis (Myotis yumanensis), Californian Myotis (M. californicus), Long-eared Myotis (M. evotis), Silver-haired Bat (Lasionycteris noctivagans) and Eastern Red Bat (Lasiurus borealis) from this region. We also captured 2 Long-eared Myotis in northwestern BC. Additionally, our surveys provided range extensions of Northern Myotis (M. septentrionalis), Long-legged Myotis (M. volans), and Hoary Bat (Lasiurus cinereus). Finally, by deploying bat detectors in late autumn, and in some cases throughout the winter, we provide data about seasonal patterns for bat activity in some locations, revealing that bats in northwestern BC may be active as late as 29 October and emerge as early as 30 March, a pattern similar to that observed in southern BC. By combining data from several disparate surveys, conducted for different reasons by different researchers, we were able to provide a fuller picture of the bat fauna of this vast region. Our data provides further evidence that the bat fauna of northwestern Canada is richer than previously documented.

Data on the summer bat fauna of Belarus in 2017–2020

This report presents the results of the bat fauna survey carried out in Belarus during the warm seasons between 2017 and 2020. The presented data were collected in 31 localities in all six administrative regions (voblasćs) of Belarus during field studies (mist-netting, searching for roosts and colonies, and acoustic surveys) and in the course of the work of the Minsk bat contact centre. Field data refer to 26 localities; acoustic observations to 14 localities; and netting was carried out in 19 localities (151 ind.). The data on bats collected via the contact centre came from 6 localities (35 ind.). In the course of our survey, we recorded 13 out of the 19 species of the Belarusian bat fauna. They are Barbastella barbastellus, Eptesicus nilssonii, E. serotinus, Myotis dasycneme, M. daubentonii, Nyctalus lasiopterus, N. leisleri, N. noctula, Pipistrellus kuhlii, P. nathusii, P. pygmaeus, Plecotus auritus, and V. murinus. The occurrence of all recorded species was confirmed by direct identification. Data on breeding have been added for all recorded species except for N. lasiopterus and B. barbastellus. Data on breeding have been added for all recorded species, except for N. lasiopterus and B. barbastellus. Maternity colonies were recorded for E. serotinus, M. dasycneme (the second record of a maternity colony of the species for the entire period of research in Belarus) and M. daubentonii. The largest number of individuals recorded by the contact centre represent V. murinus; other species in descending order are E. serotinus, N. noctula, P. auritus, P. nathusii, B. barbastellus, M. daubentonii, P. kuhlii, and E. nilssonii. Among the netted individuals, P. nathusii prevailed; other species in descending order were M. daubentonii, P. pygmaeus, E. nilssonii, P. auritus, N. noctula, E. serotinus, M. dasycneme, N. leisleri, and N. lasiopterus. Three species (V. murinus, B. barbastellus, and P. kuhlii) were presented only among bats reported via the contact centre. During the survey, the species P. pipistrellus, Pl. austriacus, M. brandtii, M. nattereri, M. myotis, and M. mystacinus included in the list of mammal species of Belarus were not recorded. The reasons of the lack of records of these six species are discussed. The collected data contribute to the general knowledge on the distribution, breeding, and status of bat species in Belarus and Eastern Europe.

Bats of Mount Silabur, Sarawak, and Its Potential for Conservation

Karst landscape is recognised as one of the biologically important areas especially for bats. The limestone caves and forest within the landscape provide essential resources for the local bat fauna, albeit bat populations are severely threatened by anthropogenic disturbances occurring within and surrounding the ecosystem. In Sarawak, studies on bat diversity are biased towards protected areas, leaving aside non-protected areas including private lands such as Mount Silabur. Surveys on bat diversity were conducted at the limestone outcrop and the surrounding matrix of Mount Silabur with the primary aim of developing the first checklist of bats at Mount Silabur. A total of 27 species were recorded from 12 sampling nights representing approximately 34% of the total bat species recorded in Sarawak. The Cox’s Roundleaf Bat (Hipposideros coxi), a rare Bornean endemic species, was recorded from the cave system, signifying an important record for the area and also Sarawak. Furthermore, this is the sixth locality record for the species in Sarawak, Borneo. Interestingly, the total number of bat species recorded from Mount Silabur represented about 72% of the total bat species recorded (27 out of 38 species) from other major touristic caves in western Sarawak; Fairy Cave Nature Reserve and Wind Cave Nature Reserve. This warrants a need to develop an action plan to protect and conserve Mount Silabur cave system and the surrounding forest for its potential to serve as a shelter for bats and other cave and forest dependent taxa. The local community should implement and adhere to guidelines for cave related activities to minimise human driven disturbances on the ecosystem and its inhabitants.

Geometric Morphometrics Analysis of Inter-Population Wing Shape Variations in Bats

Background: The cryptic diversity of bat fauna in Pakistan demands to incorporate an efficient and reliable approach for morphological species identification. The traditional taxonomic approaches are effective in exploring variations of characters but have proved to be less efficient in quantifying the interspecific and intraspecific differences. Geometric morphometric method has recently act as an efficient tool to analyze the overall changes in shape and size of biological features. The present study is therefore conducted to exploit the use of geometric morphometric methods along with traditional morphological measurements to examine the size and shape differences among four geographically isolated population groups of insectivorous bat species (Pipistrellus coromandra). 
 Methods: Specimens were collected from different locations of Punjab, Pakistan. Twelve well-defined landmarks to quantify the variation in right wing of bats were analyzed using geometric morphometric tools and wing measurements of 5 selected parameters were also taken using traditional morphological measurements. 
 Results: The results of external measurements for wing overlapped for most part among the different studied population groups. Fur colour photographs displayed in the inter-population had shown visible change from dark brown to light brown giving an indication of more morphological differences. Regarding the geometric morphometric results, wing-shape differences were found to dominate in inter-population as compared to intra-population for bats species (Pipistrellus coromandra) which clearly reflects the effects of habitat factors on different populations phenotypically. The wireframe for the first two PCs indicated an overall shape change trend with the displacement of landmark points representing the expansion along the upper wing margins in PC1 compared to PC2. 
 Conclusion: The current study has successfully explored the power of geometric morphometric in reflecting the variations in wing shape among different populations of bats species (Pipistrellus coromandra).

Uncertainty and ignored information in the analysis of bat ultrasound: Bayesian approximation to the rescue

Bat ultrasound analysis has been around for several decades and it is one of the most important tools in studies of bat ecology. Discrimination between species is based on intra-specific features of echolocation calls. Identification of species and genera in audio files can be attempted either manually or through software which performs a fully automated discrimination between species. However, significant overlap in various features (e.g. frequencies of calls) exists between species and even genera. Species ID is therefore often not an absolute conclusion, but rather an opinion or best guess, as opposed to DNA tests or measurements on external characters of captured bats. To make things even worse, the probability of actually observing a bat of a given species in space and time is ignored when performing bat ultrasound analysis. This study introduces Bayesian approximation through a new method we have named Alternative Bayesian Bat Analysis (ABBA). We show, through a simple proof-of-concept example, the importance of adding information about the local composition of the bat community, hence making informed decisions regarding which species is most likely present in audio files. The superior performance of ABBA is also shown through an example using R code. Here, we use simulated data for three Pipistrellus spp., a genus with significant overlap in frequencies, but the code can easily be adapted to other bat species and genera worldwide. ABBA outperformed the non-Bayesian approach for all three species. The rare species in the simulated data set was super-inflated when using the non-Bayesian method. Further the results show, contrarily to common belief, that the frequency dominated by a given species in a data set, depends on the composition of the bat fauna and not just means and SDs reported in the literature. ABBA allows researchers to include all observations in statistical modeling, rather than excluding observations, an approach which can affect the reliability of studies. This study also, to a great extent, explains the poor performance of software attempting automated bat ID. Implementing Bayesian algorithms, and thereby allowing users to interact with the software, should significantly improve their performance.