Nyctalus Lasiopterus Research Articles

Of greater noctule “migration” from Russia to Italy: a comment on Vasenkov et al. (2023)

We comment on a recent study (Vasenkov et al. in Dokl Biol Sci 513:395–399, 2023, https://doi.org/10.1134/S0012496623700746) presenting the movement paths of three greater noctule bats (Nyctalus lasiopterus), two juveniles and an adult, tracked from Russia in September–October 2020 and 2021, with particular emphasis on the unprecedented straight-line migration of a juvenile male to Italy. Notably, the juvenile's extraordinary 2515 km migration marks the longest recorded (as the crow flies) movement in a bat species. We argue that the two juveniles may represent cases of dispersal. Despite the attention garnered by Vasenkov et al.’s findings, caution is warranted in interpreting the broader migration picture. The paper’s dissemination underscores a potential oversimplification, neglecting key insights from recent work conducted in Italy that documented the year-round presence, hibernation, and parturition of N. lasiopterus in an area of the Friuli Venezia-Giulia region where the juvenile male tracked from Russia stopped over. Besides, inferring the existence of migratory routes based on small numbers of tracked bats is insufficient. The oversight of these findings may imply a misleading narrative about the species' behaviour, likely representing a case of partial migration, a pattern widespread among migratory bat species.

A chromosome-level genome assembly of an avivorous bat species (Nyctalus aviator)

Currently, three carnivorous bat species, namely Ia io, Nyctalus lasiopterus, and Nyctalus aviator, are known to actively prey on seasonal migratory birds (hereinafter referred to as “avivorous bats”). However, the absence of reference genomes impedes a thorough comprehension of the molecular adaptations of avivorous bat species. Herein, we present the high-quality chromosome-scale reference genome of N. aviator based on PacBio subreads, DNBSEQ short-reads and Hi-C sequencing data. The genome assembly size of N. aviator is 1.77 Gb, with a scaffold N50 of 102 Mb, of which 99.8% assembly was anchored into 21 pseudo-chromosomes. After masking 635.1 Mb repetitive sequences, a total of 19,412 protein-coding genes were identified, of which 99.3% were functionally annotated. The genome assembly and gene prediction reached 96.1% and 96.1% completeness of Benchmarking Universal Single-Copy Orthologs (BUSCO), respectively. This chromosome-level reference genome of N. aviator fills a gap in the existing information on the genomes of carnivorous bats, especially avivorous ones, and will be valuable for mechanism of adaptations to dietary niche expansion in bat species.

Maternity roosts of the giant noctule, Nyctalus lasiopterus, in preserved and disturbed forests of the Western Carpathians

Maternity roosts of the giant noctule, Nyctalus lasiopterus, in preserved and disturbed forests of the Western Carpathians

Dangerous neighbours: Birds and bird-eating bats sharing tree cavities.

Mounting evidence indicates the non-consumptive effects of predators significantly impact prey physiology, ecology and behaviour. Passerine birds experience adverse effects on nesting and reproductive success when in proximity to predators. Fear of predators is context-dependent and influenced by hunting habitats and foraging strategies. While some bat species prey on birds, the greater noctule (Nyctalus lasiopterus) stands out by specialising in avian prey, especially during peak bird migration. N. lasiopterus is thought to seize avian prey in flight, but direct evidence is lacking. If birds were taken from nests, they would likely avoid nesting near these bats. However, no observations support this view. This study documents the successful reproduction of Eurasian blue tits (Cyanistes caeruleus) nesting alongside a colony of approximately 25 greater noctules. This bird species is a prey species for greater noctules in Italy. Over about 1 month (April-May 2023), we observed parent birds provisioning food to chicks, with at least two chicks alive and fed outside the tree cavity by the end of the period. While acknowledging the limitations of a single observation, we propose that this previously unknown behaviour indirectly supports the idea that greater noctules only capture avian prey in flight, not within confined spaces. This observation challenges the perception that these bats pose a threat when sharing roosting spaces in trees, as evidenced in our observed case. We hope this novel observation inspires future research on variations in bird nesting behaviour and reproductive success in the presence of bird-eating bats, as well as an assessment of the long-term impact on population dynamics and reproductive success of nesting birds sharing such roosting spaces.

Bats (Chiroptera, Vespertilionidae) of the Bashkiria National Park

In 2018, 2019, 2021 and 2022 in the national park “Bashkiria” located in the southeastern part of the Republic of Bashkortostan, studies of the local fauna of bats (Mammalia: Chiroptera) were carried out. The uniqueness of the specially protected natural area lies in the presence of linden-maple-oak forests located on the eastern border of their range and a wide variety of surface and deep relief forms associated with the development of karst rocks. As a result, data on the habitation of 12 species of bats, which belong to six genera of the Vespertilionidae family, were obtained. Of these, eight species are included in the regional Red Book. The species Nyctalus lasiopterus, listed in the Red Book of the Russian Federation, was found in the Republic of Bashkortostan for the fi rst time. A cadastre is presented with a description of the places of work, geographical coordinates and results of catches, information on wintering places, the nature of stay in the region, reproduction, age and sex composition of populations, indicators of relative abundance. According to traps, the most numerous in the national park are: Pipistrellus nathusii, Vespertilio murinus, Myotis brandtii, Nyctalus noctula, M. daubentonii and Plecotus auritus. Few species are: Eptesicus nilssonii, M. mystacinus, N. leisleri and M. dasycneme, while M. nattereri and N. lasiopterus are rare. In addition to the identifi ed species, Pipistrellus pygmaeus, discovered by us 30 km south of the borders of the national park, can live on the territory. Recommendations on the protection of bats and the introduction of N. lasiopterus into the Red Book of the Republic of Bashkortostan are presented.

Structure of ectoparasite communities of Nyctalus species (Chiroptera: Vespertilionidae) in the Zhiguli State Nature Reserve and Samarskaya Luka National Park (European Russia)

The ectoparasites of the bats (Chiroptera) often act as carriers of infectious agents dangerous to animals and humans. This determines the relevance of studying ectoparasite communities. In this regard, the composition of communities and interspecific relations of ectoparasites of migratory bats are of particular interest, since they can be a source of arthropods with vector potential that are atypical in a studied area. This research was aimed to study the species composition, community structure and parasite-host specificity of ectoparasites in syntopic populations of bats of the genus Nyctalus. The study has been carried out in the Zhiguli State Biosphere Reserve and Samarskaya Luka National Park (Russia). A total of 78 individuals of Nyctalus were examined, namely Nyctalus noctula (47 individuals), N. leisleri (21 individuals) and N. lasiopterus (ten individuals). They were captured by ornithological nets in the summer period in 2017–2019. The collected ectoparasites were fixed in alcohol, and permanent preparations were made using Fora-Berlese liquid. In total, we found 19 ectoparasite species, namely one Hemiptera species (Cimex lectularius), four Ischnopsyllidae species, and 14 species of Spinturnicidae and Macronyssidae families. Of these, eight ectoparasite species have been found for the first time in Russia on Nyctalus species. Nine ectoparasites species were found on Nyctalus leisleri, 15 species on N. noctula, and 11 species on N. lasiopterus. The most massive and widespread parasite on Nyctalus is Macronyssus flavus. In addition, we demonstrated a high infestation of Nyctalus noctula by Spinturnix acuminatus and Steatonyssus noctulus, of Nyctalus lasiopterus by Spinturnix acuminatus and of Nyctalus leisleri by Steatonyssus spinosus. Among casual parasites of Nyctalus, there are Spinturnix helvetiae, S. myoti, S. plecotinus, Ischnopsyllus octactenus, I. variabilis, Macronyssus ellipticus, and Steatonyssus periblepharus. The correspondence analysis of certain ectoparasite communities, differing in qualitative and quantitative composition, with the host species demonstrated the general structure of parasite-host relationships. Nyctalus noctula has the highest diversity of ectoparasite communities and the model of the log-normal distribution of species abundance confirmed this. In terms of species composition, the parasite communities of Nyctalus noctula and N. lasiopterus were the most similar, while the parasite communities of Nyctalus noctula and N. leisleri were the least similar. The key components involved in the differentiation of ectoparasitic communities were the following species: Spinturnix acuminatus, S. kolenatii, Steatonyssus spinosus, and Macronyssus flavus, which have different infestation values in their hosts. Co-occurrence analysis revealed a strong positive relationship for 28 ectoparasite species pairs and a strong negative relationship for 26 species, which may be explained by weakened competitive relations between the ectoparasites. The observed assortativity of parasite species among themselves has been discussed.

Bat droppings collection by ants in epigean environments

Abstract Ants can be found in insect communities associated with droppings, but most studies about this interaction have been carried out in subterranean environments, specifically in the study of the interaction between ants and bat guano. In this report, we describe the first case of interaction between seven different ant species and the droppings of two bat species in epigean environments. The study was performed in bat roosts monitored from March to October 2022 in the Doñana Biological Reserve of the Doñana National Park (Huelva, SW Spain). It was carried out via direct observations of droppings deposited on the ground surface or in tree‐mounted dropping collectors below bat boxes. We report a total of 37 interactions by seven different species of ants with droppings of two species of bat, the soprano pipistrelle (Pipistrellus pygmaeus) and the greater noctule (Nyctalus lasiopterus), in four different habitats (Eucalyptus camaldulensis, Pinus pinea, Populus alba and ground surface). The generalist characters and the omnivorous diets of the ant species observed, in addition to the abundant availability of droppings during a period of food scarcity, suggest that droppings are transported as a food resource, with the consequent implications that this interaction may have on faecal degradation and nutrient cycling, as one of the supporting services provided by ants.

Autumn Migration of Greater Noctule Bat (Nyctalus Lasiopterus): through Countries and over Mountains to a New Migration Flight Record in Bats

—For the first time, using GPS-GSM trackers, long-term seasonal flights of greater noctule bat (Nyctalus lasiopterus) from summer habitats in Russia to wintering areas in Europe are recorded. One of the seasonal migratory flights is a record distance for bats (2515 km). The maximum daily flight was 445 km. One of the animals abruptly changed the direction of migration from southwest to north on the third day of flight after crossing the Kursk magnetic anomaly.

AUTUMN MIGRATION OF THE GREATER NOCTULE BAT (<i>NYCTALUS LASIOPTERUS</i>): ACROSS COUNTRIES AND MOUNTAINS TO A NEW RECORD FOR THE RANGE OF SEASONAL FLIGHTS OF BATS

For the first time, using GPS-GSM trackers, long-term seasonal flights of greater noctule bat (Nyctalus lasiopterus) from summer habitats in Russia to wintering areas in Europe have been recorded. One of the seasonal migratory flights is a record distance for bats (2515 km). The maximum daily flight was 445 km. One of the animals abruptly changed the direction of migration from southwest to north on the third day of flight after crossing the Kursk magnetic anomaly.

Continuous low-intensity predation by owls (Strix aluco) on bats (Nyctalus lasiopterus) in Spain and the potential effect on bat colony stability.

Owls prey on bats, but information on owl predation is scarce, its impact on bat mortality is unclear, and reports on behavioural responses, including roost-switching and fission-fusion behaviour, are equivocal. To study the link between owl predation and anti-predator behaviour in bats, we evaluated seven months of video recordings at roosts and the behaviour of 51 passive integrated transponder (PIT)-tagged bats and bats without tags in a geographically isolated colony of greater noctule bats (Nyctalus lasiopterus) in Spain. We found the tawny owl Strix aluco to almost continuously hunt N. lasiopterus, from perches and on the wing, well after the bats emerged at dusk and when they returned to their roosts. We recorded 39 unsuccessful and three successful attacks. Nonetheless, we found no evidence that owl predation modifies bat behaviour. While the bats constituted only a very small proportion of the owls' diet, owl predation accounted for an estimated 30-40% of bat mortality, which may have a significant impact on small, local or isolated bat populations, in particular, and thereby shape regional bat distributions. We hypothesize that low roost availability may also affect the bats' potential response to predation, which could lead to natural predation having an excessive impact on bat populations.

Forest islands in farmland provide vital roost trees year-round for giant and common noctule bats: Management implications

Forest islands in agricultural landscapes may be vital for biodiversity conservation, providing habitats for a variety of species, including bats. Our study focused on a forest island in NE Italy, where we observed mixed-species groups of giant (Nyctalus lasiopterus) and common (Nyctalus noctula) noctules roosting at the site. The giant noctule is highly endangered across Europe, and our findings shed light on its roosting preferences, providing key information to inform sustainable forestry practices that take this species into account. Using photographic methods and direct observation, we established that both common and giant noctules occur year-round in the forest island, with giant noctules giving birth, hibernating, and probably mating there. The bats preferred aspen trees and trees rich in cavities with high canopy closure and reduced sun exposure found in the forest interior, while they avoided forest edges. Rot cavities were frequently used, but we found no selection for cavity type, entrance height, or aspect. Despite the common belief that forestry activities in winter have negligible impact on bats, the felling of roost trees during this time can result in significant bat mortality since both common and giant noctules use these trees for hibernation. The number of cavities in a tree is a reliable predictor of a noctule roost, so it is advisable, year-round, to protect trees with cavities. Sustainable forestry practices should incorporate measures to provide roosting opportunities for bats, especially noctules. Our study only pertains to a single forest fragment. While our findings are novel and informative and highlight the conservation value of the forest island we studied, at this stage, they should not be generalized to all forest islands. We, therefore, encourage further large-scale studies to determine whether other forest islands are used similarly and to assess the broad-scale conservation implications of our work, particularly for threatened species such as the giant noctule.

Two additional sites and first evidence of wintering of the greater noctule bat, Nyctalus lasiopterus (Schreber, 1780) in Croatia

This paper presents information about two additional sites of the Greater Noctule Bat, Nyctalus lasiopterus, in Croatia. The first site is the first wintering record of this species in Croatia. It is the first record in the continental part of Croatia. The second site refers to an animal that was found dead on a windfarm in the Mediterranean region of Croatia.

Molecular identification of Eimeria species in Spanish bats.

This is the first study reporting the detection and molecular characterization of Eimeria in bats in Spain, specifically in 12 of 32 chiropteran species described in the Iberian Peninsula. A total of 76 faecal samples were collected from different bat roosting sites across Spanish territory. The DNA was extracted from the samples and sequenced by targeting the Eimeria SSU-rRNA gene. Two Eimeria species were detected in 29 of the 76 faecal samples (38%), and the bat-specific Eimeria rioarribaensis and rodent-specific Eimeria jerfinica were detected in 4 (5%) and 25 (33%) of the samples, respectively. This is the first report of E. rioarribaensis in the bats Rhinolophus euryale, Myotis myotis and Nyctalus lasiopterus, extending the host and geographical ranges for this bat coccidian parasite. The identification of the rodent-specific parasite species E. jerfinica in bats indicates the occurrence of this species in Spain, although its presence has not previously been reported in wild rodents in this country. Considering that most of the Eimeria spp. reported in bats were described only on the basis of morphometric data, molecular studies are required to determined which Eimeria species occur in bats, to complete the identification of these species and to clarify the phylogeny.

Assessing future shifts in habitat suitability and connectivity to old-growth forests to support the conservation of the endangered giant noctule.

Suitable climate and availability of habitats for roosting, foraging, and dispersing are critical for the long-term persistence of bat species. The giant noctule (Nyctalus lasiopterus) represents one of the lesser-known European bats, especially regarding the environmental factors which shape its distribution. We integrated climate-based ecological niche models with information about topography and rivers' network to model weighted suitability for N. lasiopterus in the western Palearctic. The weighted suitability map was then used to estimate connectivity among the distinct occurrence localities of N. lasiopterus, as well as from these latter towards European old-growth forests, under current conditions and different combinations of future timeframes (2030, 2050, 2070) and shared socioeconomic pathways (SSPs 3.70 and 5.85). Current weighted suitability is highest in Andalusia, northern Iberia, southwestern France, peninsular Italy, coastal Balkans and Anatolia, with dispersed suitable patches elsewhere. A north-eastward shift of weighted suitability emerges in the considered future scenarios, especially under SSP 5.85. The major current ecological corridors for N. lasiopterus are predicted within a 'belt' connecting northern Spain and southwestern France, as well as in the Italian Alps. However, following changes in weighted suitability, connectivity would increase in central-eastern Europe in the future. The bioclimatic niche of the western N. lasiopterus populations does not overlap with those of the central and eastern ones, and it only overlaps with climatic conditions characterizing old-growth forests in western Europe. The outcomes of our analyses would help in designing specific conservation measures for the distinct groups of giant noctule populations, favoring the possibility of range expansion and movement towards forested habitats.

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.

Forest bats in Southern Salamanca (Spain): rare or understudied? Insights from a highly diverse community

Forest-dwelling bats are a poorly studied group in Iberia. Little information is available about their abundance, conservation status, and, for some regions, even their distribution. This is the case in the western sector of the Sistema Central mountain range, an interesting area from a biogeographical point of view that potentially could host rich bat communities. However, there is almost no published information about forest bats in the region. From 2017 to 2019 we carried out acoustic and mistnetting surveys in the province of Salamanca (Western Spain), intending to fill this gap in the faunistic knowledge of the area. Our work has revealed a very diverse bat community, reaching 19 species out of the 31 known in Iberia. We obtained new data for forest-specialist species, including many records of the rare Myotis bechsteinii, Barbastella barbastellus and Nyctalus lasiopterus. Most interestingly, we also found a high abundance of Myotis mystacinus which is rarely captured. This study provides novel information about the distribution, status, and ecology of bats in the forests of one western sector of Sistema Central and highlights the importance of the area for conserving these species in the Iberian context. The large number of new records emphasizes the lack of sampling in the region and the need to get better knowledge to develop informed management and conservation decisions.

The First Record of the Greater Noctule Bat (Nyctalus lasiopterus) in the Southern Urals

The First Record of the Greater Noctule Bat (Nyctalus lasiopterus) in the Southern Urals

We eat meat: a review of carnivory in bats

Abstract Some bat species in the families Phyllostomidae, Megadermatidae, and Nycteridae have long been known to consume terrestrial vertebrates and, more recently, reports of aerial‐hawking vespertilionid carnivores have surfaced. We review the diets, hunting behaviour and roosting ecology of 17 bat species that are known to consume terrestrial vertebrates: Vampyrum spectrum, Chrotopterus auritus, Trachops cirrhosus, Macroderma gigas, Megaderma (Lyroderma) lyra, Nycteris grandis, Nyctalus lasiopterus, Nyctalus aviator, Ia io, Antrozous pallidus, Cardioderma cor, Phyllostomus hastatus, Mimon (Gardnerycteris) crenulatum, Mimon cozumelae, Tonatia saurophila, Tonatia bidens, and Lophostoma silvicolum. Data on their diet and roosts were obtained from 241 original works, with considerable differences in the amount of research and information available among species. Carnivorous bats were found to belong to an ecologically diverse group and share little but their diet. Therefore, we define a carnivorous bat as a bat that, either year‐round or seasonally, uses terrestrial vertebrates as the main component of its diet, at least in part of its geographic range. We conclude from available data that Mimon crenulatum, Lophostoma silvicolum, Mimon cozumelae, Phyllostomus hastatus, Tonatia bidens, Tonatia saurophila, Cardioderma cor, and Antrozous pallidus use vertebrates as a minor part of their diet and should not be considered carnivorous. The nine other species we reviewed do fit into the definition of carnivorous bats, and can be further subdivided based on their ecology and the seasonality of their habits into three categories: year‐round predominantly gleaning carnivores (Chrotopterus auritus, Trachops cirrhosus, and Vampyrum spectrum), seasonal predominantly gleaning carnivores (Megaderma lyra, Macroderma gigas, and Nycteris grandis) and seasonal aerial‐hawking bird‐eating carnivores (Ia io, Nyctalus aviator, and Nyctalus lasiopterus).

Видове різноманіття кажанів (Chiroptera) в Українському Приазов’ї та особливості їхнього перебування за сезонами

The article presents the results of regional surveys of bats in 2010–2020 in places planned for the construction of wind farms. With the use of modern ultrasonic detectors, computer programs and an electronic library of voices, 15 species were found in the Ukrainian Azov Region. Their highest diversity (11–13 species) was revealed in places of intensive migration. First of all, these are the sites Armyansk, Chaplynka, and Askania-Nova, which are located between the Dnieper valley and the Crimean Peninsula. Probably, in this area, bats migrating from the northern and north-eastern regions cross the land and join those moving along the Azov coast. The movement of a significant number of animals is noticeable in the west of the Molochna River. A relatively large variety of bats occurs near the sites Botiyevo, Orlivka, and Primorsk, located directly on the northern shore of the Sea of Azov, along which the migratory movements of bats are particularly strong. During winter, with limited research in this period, 8 species were found, whereas 13 species during spring and autumn migrations and 11 species in summer. The almost complete transformation of the steppe into agrocoenoses bordered by forest belts and irrigation canals undoubtedly affected bats in addition to global warming. In recent years, in all places of the Ukrainian Azov Region, there has been a decline in the number of the common pipistrelle (Pipistrellus pipistrellus) and serotine bats (Eptesicus serotinus), and an increase in the abundance of the noctule bat (Nyctalus noctula), Kuhl's pipistrelle (Pipistrellus kuhlii), Nathusius' pipistrelle (Pipistrellus nathusii), and parti-coloured bat (Vespertilio murinus). In all seasons, the least common species were the brown long-eared bat (Plecotus auritus), Daubenton's bat (Myotis daubentonii), greater noctule (Nyctalus lasiopterus), lesser noctule (Nyctalus leisleri), Savi's pipistrelle (Hypsugo savii), and western barbastelle (Barbastella barbastellus).

Who's for dinner? Bird prey diversity and choice in the great evening bat, Ia io.

The mysterious predator–prey interaction between bats and nocturnally migrating birds is a very rare and incredible process in natural ecosystems. So far only three avivorous bat species, including two noctule bats (Nyctalus lasiopterus and Nyctalus aviator) and the great evening bat (Ia io), are known to regularly prey on songbirds during nocturnal avian migration. The information related to the diversity and the characteristics of the birds as prey and the hunting strategy in both species of noctule bats are already clear. However, the diversity of bird prey in the diet of I. io as confirmed by molecular identification remains unknown. Moreover, like hunting insects, it remains unclear whether the avivorous bats opportunistically prey on birds. Here, we used DNA metabarcoding to investigate the bird prey composition, diversity, and choice in diets of I. io. We found I. io consumed 22 species of seven families from Passeriformes with a body mass of 6–19 g, and preferentially selected small‐sized passerine birds for optimizing the benefit/risk trade‐off. Moreover, most of the species preyed upon were migratory birds, while four species were local resident birds, indicating that I. io may adopt both aerial‐hawking and gleaning strategies on songbirds as do the other two noctules. Further, I. io body mass did not influence in prey choice and predation richness on birds, suggesting I. io is an opportunistic avivorous predator. This study provides novel insights into the avian dietary ecology of I. io and completes the analysis of predator/prey interaction between three avivorous bats and nocturnally migrating birds. Our results also indicate bat predation on birds which occurs as an act of ecological opportunity may subject bats to intense natural selection pressure, causing them access to the new diet‐defined adaptive zones.