Leisler's Bat Nyctalus Leisleri Research Articles

A novel citizen science approach for large-scale standardised monitoring of bat activity and distribution, evaluated in eastern England

In many countries, bats have high conservation prioritisation owing to their trophic position, habitat associations and threat level, and many have dedicated management plans. However, poor knowledge of species' ecology, identification issues and surveying challenges mean that large-scale monitoring to produce required distribution and abundance information is less developed than for some other taxa. Static detectors deployed to record bats throughout whole nights have been recommended for standardised acoustic monitoring but to date their cost has prohibited wide uptake. Here we describe an extensive survey approach in which members of the public borrowed detectors to participate in a large-scale monitoring and mapping project. Covering a 15% sample of the study area over two years, the survey generated over 600,000 bat recordings. We describe a semi-automated step-wise method for processing this large volume of recordings to assign identity to species or genus level with low error rates. Twelve species were recorded during the survey, ranging from the near ubiquitous Common Pipistrelle Pipistrellus pipistrellus to the locally scarce Leisler's bat Nyctalus leisleri. We show pronounced patterns of seasonality consistent with post-breeding dispersal and new information on nocturnal activity patterns. Using regression trees we generate new maps of standardised variation in activity which is likely to reflect underlying spatial variation in relative abundance. These reveal hitherto unknown patterns for species of superficially similar status. We conclude that with logistical support and centralised automated species identification it is now possible for the public to contribute to acoustic bat monitoring at an unprecedented scale.

Echolocation Calls of Bats from Madeira Island: Acoustic Characterization and Implications for Surveys

Acoustic surveys represent a powerful tool to assess bat distribution and habitat preferences and are widely applicable to monitoring and conservation schemes. However, their correct application requires the development of robust and reliable identification procedures. Little information is available on the bats of Madeira Island (Portugal), particularly their ecological requirements, distribution and population trends, and proper guidelines for their monitoring and conservation have yet to be defined. In this study, we present the first analysis of echolocation calls from species occurring on the island to provide a tool for bat identification during acoustic surveys. Seven hundred and ninety one time-expanded recordings of search phase echolocation calls in cluttered and uncluttered habitats of the Macaronesia endemic pipistrelle Pipistrellus maderensis, Madeira Leisler's bat Nyctalus leisleri verrucosus and grey long-eared bat Plecotus austriacus were analysed and an acoustic repertoire with their temp...

Mitochondrial DNA variation and population structure of the island endemic Azorean bat (Nyctalus azoreum).

The Azorean bat Nyctalus azoreum is the only endemic mammal native to the remote archipelago of the Azores. It evolved from a continental ancestor related to the Leisler's bat Nyctalus leisleri and is considered threatened because of its restricted and highly fragmented distribution. We studied the genetic variability in 159 individuals from 14 colonies sampled throughout the archipelago. Sequences of the D-loop region revealed moderate but highly structured genetic variability. Half of the 15 distinct haplotypes were restricted to a single island, but the most common was found throughout the archipelago, suggesting a single colonization event followed by limited interisland female gene flow. All N. azoreum haplotypes were closely related and formed a star-like structure typical of expanded populations. The inferred age of demographic expansions was consistent with the arrival of founder animals during the Holocene, well before the first humans inhabited the Azores. Comparisons with a population of N. leisleri from continental Portugal confirmed not only that all N. azoreum lineages were unique to the archipelago, but also that the current levels of genetic diversity were surprisingly high for an insular species. Our data imply that the Azorean bat has a high conservation value. We argue that geographical patterns of genetic structuring indicate the existence of two management units.

Seasonal patterns in activity and habitat use by bats (Pipistrellus spp. and Nyctalus leisleri) in Northern Ireland, determined using a driven transect

AbstractThe seasonal activity of Leisler's bat Nyctalus leisleri and pipistrelle bats Pipistrellus spp. with respect to minimum bat numbers and habitat use were investigated in County Down, Northern Ireland using a driven transect from April 1998 to October 1998. Data were collected in lowland farmland near Belfast, Northern Ireland using two BatBox III bat detectors tuned to detect both species and species groups simultaneously. The number of bats/km increased during April, May and June, peaking in July and tailed off after this period. The main peak in July is assumed to reflect the occurrence of newly volant young. An increase in the number of pipistrelle social calls during August and September probably represented mating activity. Bat activity correlated with temperature in both N. leisleri and Pipistrellus spp., although bat numbers were independent of temperature after the middle of June. There was significant variation in habitat use by pipistrelle bats along roads over the study period. Pipistrelle bats were observed in greater numbers in areas of tree‐line, cut hedge (≤1 m high) and deciduous woodland, and increased further when these habitats bordered both sides of the road. Nyctalus leisleri was found in similar numbers in all habitat types and there was no seasonal variation in habitat use. The validity of this method for revealing seasonal variation in bat numbers and habitat use is discussed. Ambient climatic conditions may affect the number of bats recorded, while some species with long‐range echolocation calls, such as N. leisleri, may defy analysis of habitat associations.

Evening emergence of two nursery colonies of Leisler's bat (Nyctalus leisleri) in Ireland

AbstractAt one nursery roost of Leisler's bat Nyctalus leisleri, the first bat often, and over half of the colony exceptionally, left before sunset. Departure was earlier during the period of lactation, when energy demands were highest. Consequently emergence data had to be standardized to allow for this before investigating possible associations with light intensity and meteorological factors. The importance of such standardization in general is emphasized. Emergence was earlier on overcast nights and was delayed with increased light intensity. The bats in a neighbouring roost, from which fewer data were obtained, also left earlier on overcast evenings, but departure was generally later than in the first roost, and there was no evidence of its being earlier during lactation. These differences between the roosts may be at least partially explained by the difference in size of the exit holes. At both roosts departure was mainly as a series of outbursts, and this was more marked during the first half of emergence. Rate of emergence increased with colony size. It was unusual for the first bat to leave more than 30 min, or for any bat to leave over 60 min, after sunset. Heavy rain inhibited or disrupted emergence.

Analysis of the diet of Leisler's bat (Nyctalus leisleri) in Ireland with some comparative analyses from England and Germany

The diet of Leisler's bat Nyctalus leisleri was investigated by analysis of droppings collected from six mainly pastoral sites in Ireland, two sites in England (one mainly pastoral, one arable predominating) and three in Germany (in forest), and comprised mainly medium-sized and small insects caught in flight, many of which were probably from swarms. There was a major pastoral prey component, indicated mainly by Scathophaga stercoraria, Scarabaeoidea and associated Acari, at the Irish sites (estimated as 29–55%) and the English pastoral site (22%), but this was less significant elsewhere (1–12%). Insects with aquatic larvae (Ephemeroptera, Trichoptera, Chironomidae/Ceratopogonidae, Culicidae) often made up an important part of the diet (4–39%). Another distinct component, the Lepidoptera, Hemerobiidae, Chrysopidae and Ichneumonidae, which were all intercorrelated in the results, possibly indicates feeding near trees. This component was most important at the German (36–63%) and English arable (30%) locations, but of less significance at the English pastoral (11%) and Irish (2–19%, mean 6%) ones. The diets in Germany were otherwise diverse.

Analysis of the diet of Leisler's bat (Nyctalus leisleri) in Ireland with some comparative analyses from England and Germany

AbstractThe diet of Leisler's bat Nyctalus leisleri was investigated by analysis of droppings collected from six mainly pastoral sites in Ireland, two sites in England (one mainly pastoral, one arable predominating) and three in Germany (in forest), and comprised mainly medium‐sized and small insects caught in flight, many of which were probably from swarms. There was a major pastoral prey component, indicated mainly by Scathophaga stercoraria, Scarabaeoidea and associated Acari, at the Irish sites (estimated as 29–55%) and the English pastoral site (22%), but this was less significant elsewhere (1–12%). Insects with aquatic larvae (Ephemeroptera, Trichoptera, Chironomidae/Ceratopogonidae, Culicidae) often made up an important part of the diet (4–39%). Another distinct component, the Lepidoptera, Hemerobiidae, Chrysopidae and Ichneumonidae, which were all intercorrelated in the results, possibly indicates feeding near trees. This component was most important at the German (36–63%) and English arable (30%) locations, but of less significance at the English pastoral (11%) and Irish (2–19%, mean 6%) ones. The diets in Germany were otherwise diverse.