Bats In Britain Research Articles

Effect of roost management on populations trends of Rhinolophus hipposideros and Rhinolophus ferrumequinum in Britain and Ireland

After a significant population decline during the 20th century, populations of both greater and lesser horseshoe bats have increased over recent decades in Britain and populations of lesser horseshoe bats have increased in Ireland. Vincent Wildlife Trust (VWT) acquired 37 bat reserves since the 1980s with the aim to safeguard the sites and enhance the roosting and hibernation conditions in buildings that were often derelict and sub-optimal for bats. These measures have resulted in a strong population size increase of all colonies. However, populations have also been increasing throughout Britain and Ireland as a consequence of legal protection and milder winters resulting in higher survival rates. Therefore, it is not clear whether the measures that have taken place in VWT reserves have led to a greater increase than roosts that have not benefited from the same type of management. We aimed to compare population trends of horseshoe bat roosts under VWT management and non-VWT management from 1999 to 2020 in order to assess its effectiveness. For this, we analysed population trends at sites under different management types (VWT and non-VWT) for lesser horseshoe bats in Britain and Ireland and greater horseshoe bats in Britain. Our results indicated that populations in Britain under VWT management have increased by 366% (CI 225% - 580%) for greater horseshoe bats and 188% (CI 125% - 283%) for lesser horseshoe bats. Roosts that did not benefit from the same levels of management increased respectively by 164% (CI 132% - 199%) and 51% (CI 40% - 60%). In Ireland, populations of lesser horseshoe bats in VWT managed roosts increased by 217% (CI 118% - 364%) while non-VWT managed roosts remained stable (-0.44%; CI -23% - 29%). We conclude that management actions carried out by VWT of greater and lesser horseshoe bat roosts have helped populations recover at a faster rate by securing the integrity of buildings, improving access points and by providing optimal microclimatic conditions within the buildings.

Barriers and benefits: implications of artificial night-lighting for the distribution of common bats in Britain and Ireland.

Artificial lighting is a particular problem for animals active at night. Approximately 69% of mammal species are nocturnal, and one-third of these are bats. Due to their extensive movements-both on a nightly basis to exploit ephemeral food supplies, and during migration between roosts-bats have an unusually high probability of encountering artificial light in the landscape. This paper reviews the impacts of lighting on bats and their prey, exploring the direct and indirect consequences of lighting intensity and spectral composition. In addition, new data from large-scale surveys involving more than 265 000 bat calls at more than 600 locations in two countries are presented, showing that prevalent street-lighting types are not generally linked with increased activity of common and widespread bat species. Such bats, which are important to ecosystem function, are generally considered 'light-attracted' and likely to benefit from the insect congregations that form at lights. Leisler's bat (Nyctalus leisleri) may be an exception, being more frequent in lit than dark transects. For common pipistrelle bats (Pipistrellus pipistrellus), lighting is negatively associated with their distribution on a landscape scale, but there may be local increases in habitats with good tree cover. Research is now needed on the impacts of sky glow and glare for bat navigation, and to explore the implications of lighting for habitat matrix permeability.

Heavy metal contamination in bats in Britain

Toxic metals are bioaccumulated by insectivorous mammals but few studies (none from Britain) have quantified residues in bats. We measured renal mercury (Hg), lead (Pb) and cadmium (Cd) concentrations in bats from south-west England to determine how they varied with species, sex, age, and over time, and if they were likely to cause adverse effects. Residues were generally highest in whiskered bats ( Myotis mystacinus). Compared with other species, pipistrelle ( Pipistrellus spp) and Natterer's bats ( Myotis nattereri) had significantly lower kidney Hg and Pb concentrations, respectively. Renal Hg increased over time in pipistrelles but the contributory sources are unknown. Kidney Pb did not decrease over time despite concurrent declines in atmospheric Pb. Overall, median renal metal concentrations were similar to those in bats from mainland Europe and 6- to 10-fold below those associated with clinical effect, although 5% of pipistrelles had kidney Pb residues diagnostic of acute lead poisoning.

Iron age to medieval entomogamous vegetation and Rhinolophus hipposideros roost in South-Eastern Wales (UK)

Karst cave systems are well developed in Wales (UK) and, in some instances, constitute important bat roosts. Ogof Draenen, near Blaenavon in south-east Wales, is the most recent major cave discovery (1994) with already > 70 km of passages explored spanning a vertical range of 148 m. With the exception of one small chamber (Siambre Ddu) located directly above the main Ogof Draenen system, very few bats have been noticed inside. Extensive accumulations of guano, attributable to Rhinolophus hipposideros, are however found in parts of the Ogof Draenen system. In places covering many square metres and sometimes building heaps > 0.5 m thick, these represent volumes not yet found in any other cave system in the British Isles. Although the date of the abandonment of the main Ogof Draenen system as a bat roost remains unknown, six radiocarbon dates on guano from Ogof Draenen place the occupation in the Iron Age to Medieval period at least. Palynological analysis was undertaken on ten samples distributed through the cave. Comparisons were made with a moss polster and a lake mud sample from the area to provide a first approximation of the regional modern pollen rain and with two modern guano samples, one from Siambre Ddu and one from Agen Allwedd cave (5 km to the north-west) to provide a temporal comparison with the fossil guano. Agen Allwedd cave currently is one of the largest active roosts for Lesser Horseshoe bats in Britain and lies close to the present northern limit of this endangered species in Europe. The main results are that (1) the cave appears to have been used both as a summer and a winter roost; (2) most of the Ogof Draenen guano is formed within c. 1600 14C years and, if the largest heap is continuous, it has accumulated within 750 14C years, i. e. 0.16 mm yr − 1 ; 3) the fossil guano samples reflect a relatively closed oak forest with more abundant ivy ( Hedera) and holly ( Ilex) than at present; (4) insect-pollinated plants such as Ilex, Acer, Hedera and Impatiens glandulifera are over-represented in the guano samples; (5) in addition to the usual causes of bat roost decline (pesticides, pollution), in the case of Ogof Draenen, we may add entrance blocked by rock collapse and decline of the local forest cover as well as change in its composition.

Roost Selection by the Brown Long-Eared Bat Plecotus auritus

1. One of the key threats to bats in Britain is loss of suitable roost sites, but little is known about roost requirements for most species. 2. Roost selection in the brown long-eared bat Plecotus auritus was demonstrated by comparison of buildings used as summer roosts in north-east Scotland with (i) random buildings in the same area, and (ii) a set of adjacent houses located in the same habitat. 3. Buildings containing roosts were situated closer to woodland and water relative to the random houses, and also had a greater area of woodland within a radius of 0.5 km, but not at distances beyond this. This suggests that feeding habitat in the vicinity of the roost is important for roost selection. 4. When compared with adjacent houses, roosts were older, and had roof spaces divided into more compartments, which were more likely to be fully lined with rough wooden planking. 5. The temperatures inside summer roosts (mean 17.9°C) were significantly warmer than those from random and adjacent houses (mean 16.7°C). 6. These results suggest that P. auritus is selective of its roosts, relative to the houses available. 7. The selection of specific types of roosts by P. auritus has implications for the management advice provided when roosts are threatened, and conservation actions should focus on efforts to avert significant change to, or destruction of, roost sites or the woodland in their vicinity.

Foraging Habitat Preferences of Vespertilionid Bats in Britain

The selection of foraging habitats by vespertilionid bats in Britain was quantified using a stratified sample of 1030 1-km squares. Quantitative analysis of habitat preference and avoidance on a large scale indicated that bats were flexible, yet consistent in their habitat use across contrasting landscapes. Habitats associated with broadleaved woodland and water were most preferred, while arable land, moorland and improved grassland were strongly avoided. Linear vegetation features were selected in all landscapes, demonstrating the importance of habitat continuity to bats. The availability of preferred habitats was low and patchy in all landscapes, indicating that bats have specialized habitat requirements. Differences in habitat selection between landscape types and possible factors influencing habitat selection are discussed. Habitat selection analysed on a local scale demonstrated the same consistent preference for woodland, riparian and corridor habitats across 19 discrete land classes. Management policies for bats in Britain should endeavour to preserve and enhance the availability of woodland, water margins and linear corridor habitats. Lack of continuity of the landscape, loss and fragmentation of habitat patches plus deterioration of the quality of such patches may pose a threat to bat populations.

Factors Determining the Abundance of Vespertilionid Bats in Britain: Geographical, Land Class and Local Habitat Relationships

1. Transect surveys of foraging bats in a stratified sample of 1030 1-km squares in Britain were used to compare bat abundance in different land classes. 2. Bat abundance remained constant from early to late summer but varied significantly between land classes. Increased ambient temperatures caused increased local abundance of bats. High abundance occurred within arable and pastural land class groups in the south, while low abundance occurred in arable, marginal upland and upland land class groups in the north. 3. Regression analyses identified a significant negative gradient in bat abundance on a south-north axis in Britain and also on a west-east gradient within a transect across North Wales and the English Midlands. 4. Regression analyses further outlined significant relationships between bat abundance and habitat availability within seven land class groups. Habitats included in the models were similar for each land class group. In general, bat abundance was positively related to the availability of woodland, vegetation corridors, lacustrine and riverine habitats and negatively related to the availability of arable land. 5. The models quantifying the relationship between bat abundance and habitat availability presented in this paper provide a basis for predicting the suitability of sites for foraging bats and a tool for further research to test the hypotheses relating the impact of past and future large-scale land-use change on vespertilionid bat populations in Britain.

Why do Insectivorous Bats in Britain Not Fly in Daylight More Frequently?

Why do Insectivorous Bats in Britain Not Fly in Daylight More Frequently?

Toxicity and tissue distribution of pentachlorophenol and permethrin in pipistrelle bats experimentally exposed to treated timber

The dependence of bats in Britain on houses as roosts may result in them being exposed to pesticides used in remedial timber treatments. Pentachlorophenol (PCP) and permethrin are used as a fungicide and an insecticide for timber treatment, respectively. The present study investigated toxicity and distribution in body tissues of these two pesticides in pipistrelle bats. Four groups of nine to ten bats were kept in separate outdoor flight enclosures and were provided with roost boxes treated with either PCP only, permethrin, PCP/permethrin mixture or solvent only (control). At the start of the experiment, mean (±SE) PCP and permethrin concentrations on the surface of wooden blocks that had been treated in the same way as roost boxes were 69·32±6·76 mg g −1 ( n = 6) and 3·3±1·6 mg g −1 ( n = 3), respectively. All bats exposed to PCP and PCP/permethrin treated boxes died within 24 and 120 h, respectively; nine out of the ten controls survived the 32 day experimental period ( P < 0·001; both groups compared with control). Bats exposed to permethrin treated boxes survived as well as controls. Mean (±SE) carcass PCP concentration (excluding deposits on fur) of bats exposed to PCP and PCP/permethrin treated boxes was 13·11±2·52 μg g −1 BW ( n = 20). PCP burdens on fur were positively correlated with total weight of PCP in the carcass ( P < 0·001). PCP was present in fat depots, liver, kidney and the remainder of the body which, despite containing low PCP concentrations, was the main PCP reservoir (66·4±5·0% of carcass PCP load; n = 20). Total PCP in the carcass was significantly correlated with lipid weight ( P < 0·005). Permethrin was not detectable in body washes and tissues of bats exposed to PCP/permethrin mixture or permethrin.

The distribution of bats in Britain 1982‐87 as revealed by enquiries

Mammal ReviewVolume 20, Issue 4 p. 145-157 The distribution of bats in Britain 1982-87 as revealed by enquiries A. J. MITCHELL-JONES, A. J. MITCHELL-JONES Nature Conservancy Council, Northmimter House, Peterborough PE11UA, U.K.Search for more papers by this author A. J. MITCHELL-JONES, A. J. MITCHELL-JONES Nature Conservancy Council, Northmimter House, Peterborough PE11UA, U.K.Search for more papers by this author First published: December 1990 https://doi.org/10.1111/j.1365-2907.1990.tb00109.xCitations: 3AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume20, Issue4December 1990Pages 145-157 RelatedInformation

Organochlorine Residues in Adults of Six Southwestern Bat Species

Fifty adult bats collected in Arizona and Sonora, Mexico, including long-nosed (Leptonycteris sanborni), leaf-nosed (Macrotus waterhousii), pallid ( Antrozous pallidus), big brown ( Eptesicus fuscus), western pipistrelle (Pipistrellus hesperus), and Mexican free-tailed bats (Tadarida brasiliensis), were analyzed for organochlorine residues. All contained DDE (range, 0.1-160 ppm; median, 4.3 ppm wet weight basis) and DDT (range, < 0.1-550 ppm; median, 0.2 ppm). DDD was found in 38 bats, dieldrin in 16, o,p'-DDT (at 33-200 ppm) in 3, toxaphene in 3, Aroclor 1254 in 1, and Aroclor 1260 in 1. Bats with the highest residue levels were collected in or near human dwellings. The 5 herbivorous longnosed bats averaged only 0.51 ppm DDT and metabolites, whereas the others, all insectivores, averaged 46 ppm. J. WILDL. MANAGE. 40(4):677-680 Bat populations in many parts of the United States and elsewhere are declining (Barbour and Davis 1969:11-12, Stebbings 1970, 1971, Mohr 1972, Reidinger 1972). Often it is suggested that these declines are related to pesticides, to which bat populations should be particularly vulnerable because many species are insectivorous and most have low reproductive potentials. Few studies, however, have been reported on bat-pesticide interrelations. Cockrum (1969) noted the decreasing population size of the Mexican free-tailed bat in Arizona and suggested that pesticides were involved. Luckens and Davis (1964, 1965) studied the acute oral toxicity of DDT, dieldrin, and endrin to the big brown bat. They found this species extremely sensitive to DDT. Jefferies (1972) found that some bats in Britain carried at least one-third the lethal level of DDT + DDE during most of the year and very close to the lethal level after hibernation. Dunsmore et al. (1974) measured residue levels in wild bentwinged bats (Miniopteris schreibeirsii) and some dosed with DDT. They concluded that, although the wild bats carried residues below levels suggested for direct effects, the bats could be in danger if they received increased exposure. To gain a preliminary understanding of the degree to which bats are exposed to pesticides in the southwestern United States, I measured organochlorine residue levels in 50 adult bats collected during 1969-70 in Arizona and neighboring Sonora, Mexico. These bats, representing six species with various foraging and movement habits, were collected opportunistically, without regard to season, habitat, or likelihood of recent pesticide exposure. These data are from a Ph.D. thesis on file at the University of Arizona, Tucson; the study was supported by an NDEA Title IV Fellowship. I am grateful to E. L. Cockrum, University of Arizona, who first suggested the study and who gave valued help throughout; to R. E. White and J. R. Bean, Denver Wildlife Research Center, who provided facilities, equipment, and training for residue analysis; and to A. H. Jones of the Center for careful review of the manuscript.

Bats in Britain – a Status Report

A survey has been carried out on the status of bats in Britain. Of the 14 species, the status of two, the greater horseshoe and mouse-eared bats, is precarious. The survival of these and other cavernicolous species depends on the availability of underground roosts, many of which are being destroyed, or rendered uninhabitable by extensive disturbance during hibernation. Where such disturbance is prevented by a grille at the cave entrance, the number of bats using the roost increases. There is a trade in cave-dwelling bats for museums, schools and research. Large numbers of pipistrelles and other species are killed each year in buildings. In many cases, the slaughter is fruitless because the roost is subsequently reoccupied. Ignorance and fear of bats is widespread among members of the public. With the decrease in deciduous trees, fewer roosts are available for tree-dwelling species.

Longevity of vespertilionid bats in Britain

Longevity of vespertilionid bats in Britain

Longevity of Rhinolophid Bats in Britain

NUMBERED aluminium bands which are used to study the movements of bats are also of value in providing specific information concerning age1. In Britain, the first large scale bat-banding experiment was commenced in Devon in 1948 (ref. 2) and during recent years it has been gratifying to note the continued survival of a number of greater horseshoe bats (Rhinolophus ferrumequinum) banded during the early stages of that experiment. Of particular interest has been the finding, on October 28, 1967, of greater horseshoe No. 918 (male). This bat, found in a small mine adit near Holne, in south Devon, was originally banded in a cave at Buckfastleigh, about 3 miles away, on March 4, 1949. Its age, when first handled, was not known, but because for this species birth invariably occurs only in mid-summer, usually early in July, this bat could not have been born later than July 1948. At the time of its most recent finding it must therefore have been at least 19.25 yr old.

LONGEVITY OF HORSESHOE BATS IN BRITAIN

Proceedings of the Zoological Society of LondonVolume 145, Issue 1 p. 146-147 LONGEVITY OF HORSESHOE BATS IN BRITAIN First published: May 1965 https://doi.org/10.1111/j.1469-7998.1965.tb02008.xCitations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume145, Issue1May 1965Pages 146-147 RelatedInformation