Explore the vast range of titles available.

Few studies have described winter microclimate selection by bats in the southern United States. This is of particular importance as the cold-adapted fungus, Pseudogymnoascus destructans, which causes the fatal bat disease white-nose syndrome (WNS), continues to spread into southern United States. To better understand the suitability of winter bat habitats for the growth of P. destructans in this region, we collected roost temperature and vapor pressure deficit from 97 hibernacula in six ecoregions in Texas during winter 2016-17 and 2017-18. We also measured skin temperature of Rafinesque's big-eared bats (Corynorhinus townsendii), Townsend's big-eared bats (C. townsendii), big-brown bats (Eptesicus fuscus), southeastern myotis (Myotis austroriparius), cave myotis (M. velifer), tri-colored bats (Perimyotis subflavus), and Mexican free-tailed bats (Tadarida brasiliensis) during hibernation to study their use of torpor in these habitats. We found that temperatures within hibernacula were strongly correlated with external air temperatures and were often within the optimal range of temperatures for P. destructans growth. Hibernacula and skin temperatures differed among species, with Rafinesque's big-eared bats, southeastern myotis, and Mexican free-tailed bats occupying warmer microclimates and having higher torpid skin temperatures. For species that were broadly distributed throughout Texas, hibernacula and skin temperatures differed within species by ecoregion; Tri-colored bats and cave myotis in colder, northern regions occupied colder microclimates within hibernacula and exhibited colder skin temperatures, than individuals of the same species in warmer, southern regions. These data illustrate the variability in microclimates used as hibernacula by bats in Texas and suggest similar variation in susceptibility to WNS in the state. Thus, monitoring microclimates at winter roosts may help predict where WNS may develop, and where management efforts would be most effective.

Sensitivity of bats to land use change depends on their foraging ecology, which varies among species based on ecomorphological traits. Additionally, because prey availability, vegetative clutter, and temperature change throughout the year, some species may display seasonal shifts in their nocturnal habitat use. In the Coastal Plain of South Carolina, USA, the northern long-eared bat (Myotis septentrionalis), southeastern myotis (Myotis austroriparius), tri-colored bat (Perimyotis subflavus), and northern yellow bat (Lasiurus intermedius) are species of conservation concern that are threatened by habitat loss. Our objective was to identify characteristics of habitat used by these species during their nightly active period and compare use between summer and winter. We conducted acoustic surveys at 125 sites during May–August and at 121 of the same 125 sites December–March 2018 and 2019 in upland forests, bottomland forests, fields, ponds, and salt marsh and used occupancy models to assess habitat use. The northern long-eared bat and southeastern myotis (i.e., myotis bats) used sites that were closer to hardwood stands, pine stands, and fresh water year-round. We did not identify any strong predictors of tri-colored bat habitat use in summer, but during winter they used bottomland forests, fields, and ponds more than salt marsh and upland forests. During summer and winter, northern yellow bats used sites close to fresh water and salt marsh. Additionally, during summer they used fields, ponds, and salt marsh more than upland and bottomland forests, but in winter they used bottomland forests, fields, and ponds more than upland forest and salt marsh. Our results highlight important land cover types for bats in this area (e.g., bottomland forests, ponds, and salt marsh), and that habitat use changes between seasons. Accounting for and understanding how habitat use changes throughout the year will inform managers about how critical habitat features may vary in their importance to bats throughout the year.

Research Highlights: Seasonal variation in environmental conditions coinciding with reproductive and energetic demands might result in seasonal differences in species-specific habitat use. We studied a winter assemblage of insectivorous bats and found that species acted as habitat generalists during winter compared to expectations based on the summer active season. Background and Objectives: In temperate regions, seasonal fluctuations in resource availability might restructure local bat assemblages. Initially perceived to only hibernate or migrate to avoid adverse winter conditions, temperate insectivorous bats appear to also employ intermediate overwintering strategies, as a growing body of literature suggests that winter activity is quite prevalent and even common in some lower latitude areas. However, to date, most studies have exclusively assessed habitat associations during summer. Because habitat use during summer is strongly influenced by reproduction, we hypothesized that habitat associations might differ during the non-reproductive winter period. We used acoustic monitoring to assess the habitat associations of bats across a managed pine landscape in the southeastern United States. Materials and Methods: During the winters of 2018 and 2019, we deployed acoustic detectors at 72 unique locations to monitor bat activity and characterized vegetation conditions at two scales (microhabitat and landscape). We used linear mixed models to characterize species-specific activity patterns associated with different vegetation conditions. Results: We found little evidence of different activity patterns during winter. The activity of three species (hoary bat: Lasiurus cinereus; southeastern myotis: Myotis austroriparius; and tricolored bat: Perimyotis subflavus) was not related to vegetation variables and only modest relationships were evident for four other species/groups (big brown bat: Eptesicus fuscus; eastern red bat: L. borealis; Seminole bat: L. seminolus; evening bat: Nycticeius humeralis; and Brazilian free-tailed bat: Tadarida brasiliensis). Conclusions: During winter, the bats in our study were active across the landscape in various cover types, suggesting that they do not exhibit the same habitat associations as in summer. Therefore, seasonal differences in distributions and habitat associations of bat populations need to be considered so that effective management strategies can be devised that help conserve bats year round.

The susceptibility of Myotis austroriparius (Southeastern Myotis) to infection with Pseudogymnoascus destructans, the fungus that causes white-nose syndrome (WNS), is unresolved. Our goal was to provide an initial insight on WNS susceptibility of Southeastern Myotis through a combination of fungal swabbing, ultraviolet light (UV) photography, and seasonal counts of hibernating bats in 2 caves known to harbor P. destructans. We swabbed and photographed 61 Southeastern Myotis in 2 Alabama caves during the winter of 2017–2018 and photographed an additional 38 bats at 1 of these sites the subsequent winter. Of the bats swabbed during the first field season, 77% (n = 41) tested positive for P. destructans. None of the 99 bats examined and transilluminated with UV light exhibited any yellow-orange fluorescence characteristic of P. destructans infection. However, other bat species present at both sites had visible white fungal growth. Winter counts of Southeastern Myotis did not decline following the discovery of P. destructans at the hibernaculum where we had winter survey data predating WNS. Although our observations were limited in scope, these data suggest low susceptibility of Southeastern Myotis to WNS compared to other cave-hibernating species.

Myotis grisescens (Gray Bat) and Myotis austroriparius (Southeastern Bat) generally do not utilize similar habitats; however, in areas of range overlap where they both may be captured foraging in riparian areas or observed roosting in caves, it may be difficult to discriminate between them due to contradictory information found in mammal identification guides. In order to find characteristics that can reliably be used to identify these species, we examined museum specimens and live-captured individuals to obtain data on length of toe hairs, point of attachment of the plagiopatagium to the foot or ankle, forearm length, and the presence or absence of notches on the claws of feet and thumbs. The presence or absence of a notch in the claws and forearm length were found to be the most objective methods of identifying these species.

Mizroch presents an obituary for a biologist Dale W Rice, who died on Sep 13, 2017 at the age of 87. Rice was one of the foremost experts on sperm whales.

Between April and June 2016, we observed a pair of Strix varia (Barred Owl) rearing 2 chicks in a wooded, streamside city park in Valdosta, GA, and we observed 1 instance of an adult feeding a bat to a fledgling. Thirteen of 20 owl pellets collected from the area contained 37 Myotisaustroriparius (Southeastern Myotis). This species of bat was the most frequent and abundant food item during the chick-rearing period, especially before fledging and for at least 17 days after. Birds partially replaced bats in the diet during the middle of this period. Owls commonly ate crayfish and June bugs and less commonly ate fish and a variety of small vertebrates throughout the period. To our knowledge, this is the first report of bats comprising a major dietary item for Barred Owls, including food given to the chicks.

Despite recent increases in conservation interest, the distribution, habitat needs, and conservation priorities remain poorly understood for many animal species, including forest bats. In some cases, little quantitative information exists about appropriate survey methods to determine occupancy or abundance of bats in forest systems. We quantitatively compared detection probabilities between 2 commonly used survey techniques for 2 bat species that are closely associated with bottomland hardwood stands in the southeastern United States. Passive acoustic surveys of echolocation calls were more likely than systematic roost searches to detect both Rafinesque's big-eared bats (Corynorhinus rafinesquii) and southeastern myotis (Myotis austroriparius) at 7 study areas in eastern Texas. Our results confirmed that numerous repeat visits (>15 acoustic-survey-nights) are necessary to have high confidence in detecting Rafinesque's big-eared bats; however, southeastern myotis were easier to detect. Our results emphasize the importance of quantitatively assessing survey methods prior to designing or implementing widespread survey programs for bats.

Intense conversion of bottomland hardwood forests to rice and soybeans in the Mississippi River Valley of Arkansas has restricted the remaining forest to isolated fragments. Habitat fragmentation has proven to be detrimental to population sustainability of several species, and is the subject of intense study with often species and latitude specific responses. We compared both coarse land area classes and landscape fragmentation metrics from six 30 km × 30 km subsets centered on publicly owned management areas to bat captures obtained from a 2005 population study. Patch density was the strongest predictor of total captures (R2 = 0.801, p = 0.016) and of Myotis austroriparius captures (R2 = 0.856, p = 0.008). Our findings indicate that patch density and area are important predictors of bottomland bat captures.

Skeletogenesis was studied in two species of bats, Myotis austroriparius (southeastern brown bat) and Tadarida brasiliensis (Brazilian free-tailed bat), occupying a maternity roost in central Florida. These bats often use distinct maternity roost environments, so this provided an opportunity to examine differential patterns of long bone growth while fetuses and newborn developed under similar environmental conditions. Some differences in the timing of onset of osteogenesis were revealed in the bats, indicating that some elements of the hindlimb develop relatively more rapidly in T. brasiliensis than in M. austroriparius. Some variance was also noted, with similarity to other species previously studied by others, in the exact timing and elongation of both long bones, as well as carpal and tarsal bones. In contrast to many elements of the long appendicular skeleton of developing Mus musculus, the bats all exhibit relatively precocial patterns of osteogenesis during which cartilaginous precursors are replaced by bone tissue. The relative advanced timing of osteogenesis in select hindlimb bones of T. brasiliensis may account for its relatively low neonatal mortality compared to M. austroriparius newborn in the same roost.