Summer Roosts Research Articles

New Record of Northern Long-eared Bats in Coastal South Carolina

Abstract Myotis septentrionalis (Northern Long-eared Bat) is widely distributed in North America, from the Appalachians to the Maritime Provinces and west to British Columbia. In November 2016, we captured 2 non-reproductive Northern Long-eared Bats, 1 female and 1 male, in nets set in Beaufort County, coastal South Carolina. Previous records for the species indicate its nearest breeding colonies are >350 km away, and it had not been documented in South Carolina outside the Blue Ridge region. Although the Northern Long-eared Bat is known to move between summer roosts and winter hibernacula, it is not considered a long-distance migrant. Our records potentially represent an unrecognized coastal population rather than stray individuals. Such a population may be important for the survival of the species, which has been severely impacted elsewhere in its range by white-nose syndrome, a disease that is caused by the introduced fungal pathogen, Pseudogymnoascus destructans, which has not yet been recorded in coa...

Bat Activity at High Altitudes in the Central Alps, Europe

The occurrence of bats in mountains at high altitudes above 2300 m has not been investigated in the Alps until recently. In other European mountains, only a few studies on bats in high regions e.g., in the Pyrenees or in Switzerland at the Col de Bretolet had been conducted. Here we report a study carried out between 2012 and 2016 at several high-alpine sites at altitudes ranging from 2250 m up to 2761 m in the mountains of the Hohe Tauern, Salzburg, Austria. In spite of extreme climatic conditions, a surprisingly high bat activity and diversity of bat species was recorded. Eleven bat species were detected by different methods. Species identified by echolocation calls were: Barbastella barbastellus, Eptesicus nilssonii, Nyctalus noctula, N. leisleri, Pipistrellus pipistrellus, P. pygmaeus, Myotis daubentonii, and Vespertilio murinus. Additional findings were the species pairs Myotis mystacinus/M. brandtii and Pipistrellus nathusii/P. kuhlii as well as the genus Plecotus. The presence of most of these species was confirmed by capturing individuals with mist nets. Permanent monitoring of ultrasound calls was undertaken throughout the active period of bats at the site located at 2315 m above sea level. A total of over 30,000 series of bat calls were recorded and the activity period lasted from the end of March to the beginning of November. Long-distance migratory bat species were recorded in spring under wintry conditions and much more prominently from August to October. Presumably these individuals were crossing the Alps on their way between summer and winter roosts. Sedentary bats used the high alpine zone for foraging during summer. At these altitudes bats were active at high wind speeds of up to 13.9 m/s as well as at low temperatures around freezing point and down to -5.8°C.

Buckyballs and bats: trace evidence points to trophic interactions

Buckyballs and bats: trace evidence points to trophic interactions

Indiana bats roost in ephemeral, fire-dependent pine snags in the southern Appalachian Mountains, USA

The Indiana bat (Myotis sodalis), a species that is federally endangered in the U.S., is being impacted by white-nose syndrome and habitat loss across much of its range. A better understanding of summer roost ecology of the species will enable us to develop management strategies that promote summer survival for breeding adult females and their pups. We conducted a 5year investigation of Indiana bat roost habitat selection and roosting behavior in a large (>250,000ha) forested area of the southern Appalachian Mountains and compared our results to populations in different landscapes across the species’ range. From May to August 2008–2012, we attached radio transmitters to 50 adult females, 3 juveniles, and 7 adult males captured at sites on the Cherokee and Nantahala national forests and Great Smoky Mountains National Park. We radiotracked bats to 95 roosts and measured characteristics of trees, 0.1ha plots, and landscape attributes for 69 of these roosts and associated random trees. We used an AIC approach to compare 14 candidate conditional logistic regression models. The only plausible model, which carried 95% of total model weights, had 3 important terms. Indiana bats showed strong selection for yellow pine (Pinus subgenus Diploxylon) snags that were significantly taller than random trees and in areas with a greater number of snags within 0.1ha. During this study, tree and stand structure were more important for roost selection than larger scale factors and Indiana bats responded to a pulsed and highly ephemeral resource, dead yellow pines, which were a significant component of the large forest tracts. Roosting behavior differed from what has been observed for Indiana bats in other parts of the eastern U.S.; maternity colonies tended to be smaller (<25 bats, but as large as 75 bats prior to pups being volant) and bats were more nomadic, using each roost tree for only 2–3days on average and rarely for more than one year. The differences we observed in roosting behavior in the southern Appalachians suggest it would be wise to consider the broader landscape context when evaluating the roosting ecology of Indiana bats, as local forest types and disturbance events will affect stand structure and roost tree availability. Stand- and landscape-scale management practices that create or preserve large pine snags, such as prescribed fire, coupled with natural or manmade pulsed disturbances, should aid in the management and recovery of the Indiana bat in this region.

Factors driving population recovery of the greater horseshoe bat (Rhinolophus ferrumequinum) in the UK: implications for conservation

Although populations of many bat species appear to be recovering in some European countries, the extrinsic and intrinsic factors driving these increases have not yet been assessed. Disentangling the benefits of conservation management from other factors such as climate change is a crucial step for improving evidence-based conservation strategies. We used the greater horseshoe bat (Rhinolophus ferrumequinum) as a case study for understanding the recovery of bat populations, as its north-western populations have increased substantially over the past two decades following severe population declines. Using summer roost count data from the UK National Bat Monitoring Programme spanning an 18 year period from 1997 to 2014, we investigated the effects of (i) landscape characteristics associated with the implementation of the agri-environment schemes on colony trends and size, and (ii) meteorological variables on annual colony growth rate. We also assessed the relationship between colony size and colony growth to investigate intrinsic factors such as an Allee effect. Our results indicated that colony size was positively related to a range of landscape features (e.g. amount of broadleaf woodland and grassland, and density of linear features) surrounding the roost, while the amount of artificial light at night had a significant negative effect. Spring temperatures and precipitation (the latter with a lag of one year) were associated with annual colony growth. We also identified a negative density-dependence effect within colonies. Though the conservation of essential landscape elements may have contributed to population increases in the long-term, we conclude that recent population recovery has also been driven by climate change. Finally we recommend that the conservation of photophobic bat species such as R. ferrumequinum should focus on both the improvement of foraging/commuting habitats and the creation of dark areas.

Seeing the Forest through the Trees: Considering Roost-Site Selection at Multiple Spatial Scales.

Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats (Myotis sodalis) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007–2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm (Ulmus americana) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural components that are products of past and current land use interacting with environmental aspects such as landform also are important factors influencing roost-tree selection patterns.

Baseline population estimates and microclimate data for newly established overwintering Brazilian free-tailed bat colonies in central Texas

Abstract Behavioral changes of migratory species have been globally documented in recent decades. However, there is a paucity of research on changes in migratory bat species. Brazilian free-tailed bats (Tadarida brasiliensis) roost in central Texas from March to November. These bats have historically migrated south in late fall, leaving summer roosts unoccupied during winter. Recently, overwintering populations have been discovered in central Texas. The objectives of our study were to determine presence or absence of overwintering free-tailed bats at six known summer roosts, obtain baseline population estimates, and evaluate microclimates of roosts during winters of 2010–2011 and 2011–2012. We used data loggers to monitor temperature and humidity hourly. We estimated population sizes with digital images using ImageJ software, previously established roosting densities, or both. Our results indicated that occupied roosts were colder, had less stable temperatures, and had a stronger correlation between inter...

The thousand-year history of the Slovak Karst inferred from pollen in bat guano inside the Domica Cave (Slovakia)

A thousand years old 105 cm deep deposit of bat guano in the Domica Cave (southern Slovakia, Slovak Karst National Park) has been discovered for science, and three samples were analysed for pollen to identify the bats’ preferred foraging habitats and for insect remains to identify their diet. The bat species concerned, Rhinolophus euryale, is rare in the area, which lies at the northern margin of its distribution. The pollen record captured alder forests between 897–1024 AD, temperate light broad-leaved oak-hornbeam forests with Quercus cerris, Fraxinus ornus, Cornus mas and Corylus avellana between 1522–1800 AD, and almost recently willow shrubs. This pattern may, however, reflect local changes in the surrounding landscape where the bats hunted. Pollen of anemophilous taxa was underrepresented (e.g. Fagus), while entomophilous taxa were overrepresented (e.g. Fraxinus ornus, Loranthus europaeus, Acer, Agrostemma githago). The phenology of the encountered pollen taxa indicates that the bats used the Domica Cave mainly as spring and summer roosts. The pollen record further indicates that the bats prefer to forage in a forest–steppe landscape with open Pannonian broadleaved forests and humid temperate riparian environments. Today, this kind of landscape does not occur further north, which may explain the northern limit of this bat species at the study site.

Roost Site Selection in Pregnant and Lactating Soprano Pipistrelles (Pipistrellus pygmaeusLeach, 1825) at the Species Northern Extreme: The Importance of Warm and Safe Roosts

In summer reproducing female bats prefer roosts with temperatures in their thermo neutral zone, but in northern Europe, such roosts may be difficult to find. In this study, summer roost site selection of pregnant and lactating soprano pipistrelles were investigated using radio telemetry (2004–2006) in a fiord landscape with complex topography at the species northern extreme. The soprano pipistrelles' common roost sites were in hollow trees (n = 14), but they also used crevices in rock walls (n = 2) and the attic of one building. The bats exclusively sought out roosts on the north side of the fiord with the slope facing south, where solar irradiation yielded the warmest micro climate. From 2005 to 2014, bat boxes were erected at three sites in the study area. From 2012 to 2014 we only found maternity roosts in such structures, thus there was a clear shift in roost site selection by the soprano pipistrelle in the study area. Man-made structures, such as buildings and bat boxes, provided the warmest cavities, whereas natural cavities did not differ significantly from air temperatures. The bats did not find thermo neutral roosts most of the time, and this should affect the energy budgets, and thus the bats' behaviour. Direct observation of predation at roosts in build-up areas suggests that living close to humans could be costly to bats emerging in daylight conditions. No predation attempts were recorded at roosts in woodland habitats.

Return of the bats? A prototype indicator of trends in European bat populations in underground hibernacula

Monitoring data on hibernating bats were aggregated for the first time across a number of European countries. These supranational trends revealed that nine out of 16 bat species examined increased at their hibernation sites in Europe between 1993 and 2011, while only one is decreasing. This is reflected in the positive trend shown by a prototype multispecies bat indicator which combined the individual species trends. Our findings suggest that after a period of strong decline in the 20th century, populations of most of the investigated bat species are stabilising or recovering, although with profound differences between European bio-geographical regions and countries. Bat populations in the Continental region have a less positive tendency, compared to those in the Atlantic region. More data from more countries may reveal whether these differences are systematical. So far, the prototype indicator covers 9 countries and 16 of the 45 bat species found in Europe. The next steps will be to refine the methodology behind the indicator and to improve the indicator's representation of European bat populations and its capacity to compare trends among biogeographic regions. This should be achieved by participation of more countries and incorporating data from additional bat species, including data collected by other surveillance methods, such as summer roost counts. Robust information on trends in bat populations at a range of geographic scales is essential to the long-term conservation of bats. Further development of this indicator will make an important contribution to conservation of bats because it will stimulate international cooperation and capacity building for monitoring and research, thus exchanging and broadening knowledge of the status of bats and improving the identification of threats.

Cave-Dwelling Arthropods and Vertebrates of North Rim Grand Canyon, with Notes on Ecology and Management

Prior to this study, there was no information on arthropods, bats, and other vertebrates of caves in northwesternmost Arizona. Based on invertebrate and vertebrate inventory work conducted during 2005 and 2006, we provide future directions for conservation and management for caves on Grand Canyon—Parashant National Monument, northwestern Arizona. Baseline investigations to find and identify arthropods, bats, and other vertebrates were conducted at 7 of the largest known caves on the monument. We identified 52 morphospecies including 44 arthropods, 4 bats, and 4 other vertebrates. Of the cave-dwelling arthropods, we found 10 eisodophiles, 6 troglophiles, 8 questionable troglophiles, 7 trogloxenes, 8 accidentals, 3 taxa of unknown cave affiliations, and 2 mammalian parasites. We made several contributions to the entomological record including 2 new genera, 6 new species, 3 possible new species, one range extension, and one possible range extension. Also, we identified 5 bat roosts—1 hibernaculum, 2 night roosts, and 3 summer roosts of unconfirmed use. Observed arthropod richness per cave ranged from 1 to 14 morphospecies, and observed bat and other vertebrate (combined) richness was 1–3 morphospecies. We did not detect any cave-adapted arthropods during this investigation. For the caves sampled, we are uncertain whether the lack of cave-adapted taxa is due to (a) low nutrient input and high cryptoaridity associated with many southwestern cave systems or (b) lack of intensive sampling. Despite the lack of cave-adapted species, 5 of the 7 caves inventoried are considered of high management concern. Additional research at these caves will be required to obtain the data necessary to best manage and protect these systems.

Variability in Seroprevalence of Rabies Virus Neutralizing Antibodies and Associated Factors in a Colorado Population of Big Brown Bats (Eptesicus fuscus)

In 2001–2005 we sampled permanently marked big brown bats (Eptesicus fuscus) at summer roosts in buildings at Fort Collins, Colorado, for rabies virus neutralizing antibodies (RVNA). Seroprevalence was higher in adult females (17.9%, n = 2,332) than males (9.4%, n = 128; P = 0.007) or volant juveniles (10.2%, n = 738; P<0.0001). Seroprevalence was lowest in a drought year with local insecticide use and highest in the year with normal conditions, suggesting that environmental stress may suppress RVNA production in big brown bats. Seroprevalence also increased with age of bat, and varied from 6.2 to 26.7% among adult females at five roosts sampled each year for five years. Seroprevalence of adult females at 17 other roosts sampled for 1 to 4 years ranged from 0.0 to 47.1%. Using logistic regression, the only ranking model in our candidate set of explanatory variables for serological status at first sampling included year, day of season, and a year by day of season interaction that varied with relative drought conditions. The presence or absence of antibodies in individual bats showed temporal variability. Year alone provided the best model to explain the likelihood of adult female bats showing a transition to seronegative from a previously seropositive state. Day of the season was the only competitive model to explain the likelihood of a transition from seronegative to seropositive, which increased as the season progressed. We found no rabies viral RNA in oropharyngeal secretions of 261 seropositive bats or in organs of 13 euthanized seropositive bats. Survival of seropositive and seronegative bats did not differ. The presence of RVNA in serum of bats should not be interpreted as evidence for ongoing rabies infection.

Food for flight: pre-migratory dynamics of the Lesser Kestrel Falco naumanni

Capsule The post-reproductive stage of Lesser Kestrel is crucial for migratory fuelling and survival.Aims To describe the summer pre-migratory ecology of the Lesser Kestrel in Sicily and review existing data in Southern Europe.Methods We identified the main summer roosts and then made roost counts every ten days from 2010 to 2012. We used case-sensitive modelling procedures to detect biases in counts (generalized linear mixed models), assess the annual population trends from 2005 to 2012 (TRends and Indices for Monitoring); and to model habitat preferences (generalized linear model). We sampled pellets to describe the birds’ diet during the peak month prior to migration.Results We discovered five roosts in Sicily with numbers of Lesser Kestrels varying annually (mean ± sd: 2112 ± 387; min–max: 1797–2544). Counts at the main roost were not biased by meteorological conditions and showed an August peak followed by persistent decline through October. Less urbanized and heterogeneous agricultural areas with large cereal fields were the most significant habitats preferred during summer. Within this landscape, Lesser Kestrels prey on seasonally high concentrations of the small cricket Grylloderes brunneri.Conclusion Arable land not fragmented by agricultural intensification supports habitat rich with Orthopterans and attracts a large number of Lesser Kestrels fuelling before migration. Conservation of such pre-migratory habitats is as vital as conservation of breeding areas.

Is the parti-coloured bat Vespertilio murinus Linnaeus, 1758 a common bat species in Slovenia?

In the last overview of bats in Slovenia, the parti-coloured bat Vespertilio murinus was one of the rarest species listed. However, in the past few years (June 2005 - April 2013) we have found 98 new locations. In this article, we present new data on mating sites, summer roosts and hibernacula, as well as other chance encounters. Although V. murinus is a permanent part of the bat fauna in Slovenia, it is much more evident during the colder part of the year, when migrating individuals possibly reach their wintering area. We argue that this bat species is much more common in Slovenia and its neighbouring regions than previously assumed.

Diet of the insectivorous batPipistrellus nathusiiduring autumn migration and summer residence

Migration is widespread among vertebrates, yet bat migration has received little attention and only in the recent decades has a better understanding of it been gained. Migration can cause significant changes in behaviour and physiology, due to increasing energy demands and aerodynamic constraints. Dietary shifts, for example, have been shown to occur in birds before onset of migration. For bats, it is not known if a change in diet occurs during migration, although breeding season-related dietary preference has been documented. It is known that a diet rich in fats and the accumulation of fat deposits do increase the flight range of migratory bats. Some bat species can be regarded as long-distance migrants, covering up to 2000km between summer and winter roosting areas. Pipistrellus nathusii (Vespertilionidae), a European long-distant migrant, travels each year along the Baltic Sea from north-eastern Europe to hibernate in central and southern Europe. This study presents data on the dietary habits of migrating Pipistrellus nathusii compared with those during the breeding season. We analysed faecal samples from bats on fall migration caught at the Ornithological Field Station in Pape, Latvia and from samples collected in North-Latvian summer roosts. We applied both morphological identification and molecular methods, as morphological methods also recognize life stages of prey and can contribute frequency data. The diets of bats on migration and breeding bats were similar, with Diptera and Lepidoptera comprising the major prey categories. However, certain prey groups could be explained by the different hunting habitats exploited during migration vs. summer residence.

Divergent Roosting Habits of Rafinesque's Big-eared Bat and Southeastern Myotis During Winter Floods

Despite the importance of winter roosts to bat ecology, much less is known about tree roosts used by bats in winter than in summer. Rafinesque's big-eared bat (Corynorhinus rafinesquii) and southeastern myotis (Myotis austroriparius) are species of concern whose winter tree roost selection may be constrained by seasonal flooding in cypress-gum swamps. To evaluate winter roost selection by these species, we compared characteristics of winter roosts to trees not occupied in winter and to summer roost trees in the Oconee River floodplain, Laurens County, Georgia. We located 23 Rafinesque's big-eared bat winter roosts and 5 southeastern myotis winter roosts by climbing and visually inspecting hollow trees and by radio telemetry. We analyzed differences between used and unused trees in winter and between winter and summer roosts. Despite extensive flooding in winter, Rafinesque's big-eared bats roosted in cypress-gum swamps in summer and winter. Accordingly, they used similar large hollow water tupelo (Nyssa aquatica) in both seasons, although roost entrances were higher in winter. In contrast, southeastern myotis roosted in cypress-gum swamps in summer and switched to a diverse hardwood floodplain forest with shallower flood waters in winter. As a result they used smaller roosts in different tree species in winter than in summer. The divergent roosting habits in winter are likely due to the height of roost entrances in relation to flood waters. In summer Southeastern myotis use basal openings that are submerged during winter flooding, whereas Rafinesque's big-eared bats use openings located higher on the tree bole that are not submerged. Therefore, management for southeastern myotis may require provision of separate summer and winter roosting habitats.

Mating of Myotis capaccinii (Bonaparte, 1827) and other interesting autumn bat observations in the cave Rivčja jama (central Slovenia)

Rivčja jama in central Slovenia is a well researched bat summer roost; however, the autumn composition of its bat fauna is still poorly known. Therefore, we conducted mistnetting in front of the cave on 28. 9. 2011. We caught five bat species; most interesting among them were long-fingered bat (Myotis capaccinii) and lesser mouse-eared bat (M. oxygnathus), both otherwise rarely recorded in central and eastern Slovenia. Mistnets captures, together with visual observation, also confirmed mating of M. capaccinii in the cave.

Southeastern Myotis (Myotis austroriparius) Roost Selection in Cypress-Gum Swamps

Roost characteristics have been described for most North American bats, but debate continues over the ultimate mechanisms behind roost selection. Hypotheses include the need for a stable microclimate, protection from predators, proximity to foraging habitat, and availability of alternative roosts, among others. Our objective was to weigh evidence for hypotheses regarding selection of diurnal summer roosts using southeastern myotis (Myotis austroriparius) as a model. We used transect searches and radiotelemetry to locate 25 roosts at eight study sites across the Coastal Plain of Georgia, USA. We measured 22 characteristics of trees, at all occupied roosts and at randomly selected unoccupied trees. We evaluated 10 hypotheses using single-season occupancy models. The best supported model predicted bat presence based on the variables tree species, solid wood volume, and canopy cover. Because these characters affect heat retention and insolation, our results are consistent with the hypothesis that bats select ...

Long-distance movements of little brown bats (Myotis lucifugus)

were to quantify proportions of male and female bats that relocated from hibernacula and/or summer roosts between years, proportions of males and females captured at swarms that hibernated at those sites versus other hibernacula, and distances traveled by males and females during relocation events. We predicted that bats would exhibit male-biased dispersal, with males significantly more likely to relocate and more likely to travel long distances during relocation events. Between 1989 and 2010, we recaptured 1,459 of 10,432 banded individuals. Seasonal movements from hibernacula and/or swarms to summer colonies ranged widely from 10 to 647 km. Consistent with previous studies we found high fidelity to summer colonies and hibernacula across years. However, some individuals switched sites between years and the median relocation distance was 315 km, with over 20% of individual movements exceeding 500 km. Surprisingly, we found that females were significantly more likely to relocate than males. Our data could help explain apparent jumps in the distribution of G. destructans, but more data on transmission of the fungus in the wild are needed.

Staphylococcus nepalensis in the guano of bats (Mammalia)

Thirty randomly selected mesophilic isolates from the six years old guano sample from mixed Myotis myotis and M. blythii summer roosts colony were isolated and identified as Staphylococcus nepalensis using MALDI TOF analysis. 16S rRNA gene sequencing of selected five isolates and subsequent phylogenetic analysis confirmed that all sequences showed the highest similarity to S. nepalensis sequences. Several virulence factors were produced by tested isolates, mainly capsule formation and resistance to tetracycline, ampicillin, gentamycin, and chloramphenicol antibiotics. Our experiments show that the majority of cultivable mesophilic bacteria from the guano of bats belong to the S. nepalensis species. This is the first report on the occurrence of this species in the guano of bats and our results indicate that the guano accumulated near or directly in human dwellings and buildings may represent a significant risk for human health.