Bat with white-nose syndrome. Photograph by U.S. Fish & Wildlife Service.
White-nose syndrome (WNS) and/or Pseudogymnoascus destructans (P.d.), the causal agent, has spread westward across 26 states and 5 provinces within the eastern United States and Canada, respectively, over a short period of time. In 2015, three tri-colored bats (Perimyotis subflavus), a species found primarily in the eastern United States, tested positive for P.d. in eastern Oklahoma. Until March 2016, the discovery of WNS and P.d. in Washington state, these records represented the westernmost occurrence of the disease causing fungus. In addition, records of P.d from eastern Oklahoma are also on the same latitude and trajectory as a possible corridor to the western United States via northeastern New Mexico and southeastern Colorado. In 2003, tri-colored bats were discovered in northeastern New Mexico, thus suggesting that this species is moving into the West via the riparian corridors of northeastern New Mexico.
Given the proximity of Bent’s Old Fort National Historic Site (BEOL, approx. 135 km away) in southeastern Colorado and Capulin Volcano National Monument (CAVO, approx. 75 km away) in northeastern New Mexico to the record of P. subflavus recorded in 2003, these two monuments are at the frontline to the introduction of P.d. and WNS. Further, Pecos National Historic Park (PECO) is at an ecotone between grassland-woodland and montane forest relative to the two aforementioned national parks and likely possess a greater diversity of bat species that could be affected by WNS. Overall, these sites serve as critical locations prior to exposure to P.d. for the diagnosis of naturally occurring microbiota that could act as natural defenses against WNS.
During the spring and summer of 2016, FORT Scientist Dr. Ernie Valdez and his collaborators at the University of New Mexico sampled bats from all BEOL, CAVO, and PECO in an effort to document naturally occurring bacteria belonging to the group known as Actinobacteria. In general, this particular group of bacteria is known for producing many of the world’s antibiotics. As shown in previous research by Dr. Valdez and his collaborators, some Actinobacteria sampled from the external surfaces of western bats produce antifungal properties that impact the growth of P.d. (see figure 1). The discovery and future testing of the anti-fungal properties from these bacteria may lend themselves as possible bio-control agents against WNS.
Insect prey eaten by Hoary Bats (Lasiurus cinereus) prior to fatal collisions with wind turbines
Wind turbines are being deployed all across the world to meet the growing demand for energy, and in many areas, these turbines are causing the deaths of insectivorous migratory bats. One of the hypothesized causes of bat susceptibility is that bats are attracted to insects on or near the turbines. We examined insect remains in the stomachs and intestines of hoary bats (Lasiurus cinereus) found dead beneath wind turbines in New York and Texas to evaluate the hypothesis that bats die while feeding at turbines. Most of the bats we examined had full stomachs, indicating that they fed in the minutes to hours leading up to their deaths. However, we did not find prey in the mouths or throats of any bats that would indicate the bats died while capturing prey. Hoary bats fed mostly on moths, but we also detected the regular presence of beetles, true bugs, and crickets. Presence of terrestrial insects in stomachs indicates that bats may have gleaned them from the ground or the turbine surfaces, yet aerial capture of winged insect stages cannot be ruled out. Our findings confirm earlier studies that indicate hoary bats feed during migration and eat mostly moths. Future studies on bat behaviors and insect presence at wind turbines could help determine whether feeding at turbines is a major fatality risk for bats.
Continental-scale, seasonal movements of a heterothermic migratory tree bat
Long-distance migration evolved independently in bats and unique migration behaviors are likely, but because of their cryptic lifestyles, many details remain unknown. North American hoary bats (Lasiurus cinereus cinereus) roost in trees year-round and probably migrate farther than any other bats, yet we still lack basic information about their migration patterns and wintering locations or strategies. This information is needed to better understand unprecedented fatality of hoary bats at wind turbines during autumn migration and to determine whether the species could be susceptible to an emerging disease affecting hibernating bats. Our aim was to infer probable seasonal movements of individual hoary bats to better understand their migration and seasonal distribution in North America. We analyzed the stable isotope values of non-exchangeable hydrogen in the keratin of bat hair and combined isotopic results with prior distributional information to derive relative probability density surfaces for the geographic origins of individuals. We then mapped probable directions and distances of seasonal movement. Results indicate that hoary bats summer across broad areas. In addition to assumed latitudinal migration, we uncovered evidence of longitudinal movement by hoary bats from inland summering grounds to coastal regions during autumn and winter. Coastal regions with nonfreezing temperatures may be important wintering areas for hoary bats. Hoary bats migrating through any particular area, such as a wind turbine facility in autumn, are likely to have originated from a broad expanse of summering grounds from which they have traveled in no recognizable order. Better characterizing migration patterns and wintering behaviors of hoary bats sheds light on the evolution of migration and provides context for conserving these migrants.
An Integrative and Comparative Approach to Detecting and Understanding Bat Fatalities at Wind Turbines, Fowler Ridge Wind Farm, Indiana, 14 July to 3 October: Final Report
Cryan, P.C., C. Hein, M. Gorresen, R. Diehl, M. Huso, K. Heist, D. Johnson, F. Bonaccorso, and M. Schirmacher
Turbines have been used to harness energy from wind for hundreds of years. However, with growing concerns about climate change, wind energy has only recently entered the mainstream of global electricity production. Since early on in the development of wind-energy production, concerns have arisen about the potential impacts of turbines to wildlife; these concerns have especially focused on the mortality of birds. Despite recent improvements to turbines that have resulted in reduced mortality of birds, there is clear evidence that bat mortality at wind turbines is of far greater conservation concern. Bats of certain species are dying by the thousands at turbines across North America, and the species consistently affected tend to be those that rely on trees as roosts and most migrate long distances. Turbine-related bat mortalities are now affecting nearly a quarter of all bat species occurring in the United States and Canada. Most documented bat mortality at wind-energy facilities has occurred in late summer and early fall and has involved tree bats, with hoary bats (Lasiurus cinereus) being the most prevalent among fatalities. This literature synthesis and annotated bibliography focuses on refereed journal publications and theses about bats and wind-energy development in North America (United States and Canada). Thirty-six publications and eight theses were found, and their key findings were summarized. These publications date from 1996 through 2011, with the bulk of publications appearing from 2007 to present, reflecting the relatively recent conservation concerns about bats and wind energy. The idea for this Open-File Report formed while organizing a joint U.S. Fish and Wildlife Service/U.S. Geological Survey “Bats and Wind Energy Workshop,” on January 25–26, 2012. The purposes of the workshop were to develop a list of research priorities to support decision making concerning bats with respect to siting and operations of wind-energy facilities across the United States. This document was intended to provide background information for the workshop participants on what has been published on bats and wind-energy issues in North America (United States and Canada).
Surveillance for White-Nose Syndrome in the bat community at El Malpais National Monument, New Mexico, 2011
From late winter to summer 2011, the U.S. Geological Survey Arid Lands Field Station conducted mist-netting efforts at El Malpais National Monument and on adjacent lands belonging to Bureau of Land Management and U.S. Forest Service to detect the occurrence of white-nose syndrome or causal fungal agent (Geomyces destructans). During this assessment, 421 bats belonging to 8 species were documented at El Malpais National Monument and adjacent lands. None of these captures showed evidence for the presence of white-nose syndrome or G. destructans, but it is possible that the subtle signs of some infections may not have been observed.
Throughout the field efforts, Laguna de Juan Garcia was the only water source located on El Malpais National Monument and was netted on June 20 and 27, July 25, and August 2, 2011. During these dates, a total of 155 bats were captured, belonging to eight species including: Corynorhinus townsendii (Townsend’s Big-Eared Bat), Eptesicus fuscus (Big Brown Bat), Lasionycterics noctivagans (Silver-Haired Bat), Myotis ciliolabrum (Small-Footed Myotis), M. evotis (Long-eared myotis), M. thysanodes (Fringed Myotis), M. volans (Long-Legged Myotis), and Tadarida brasiliensis (Brazilian Free-Tailed Bat). Overall, Laguna de Juan Garcia had the greatest number of captures (79 bats) during one night compared to the other sites netted on adjacent lands and had the greatest species diversity of 8 species netted, not including Euderma maculatum (Spotted Bat) that was detected by its audible calls as it flew overhead. Laguna de Juan Garcia is an important site to bats because of its accessibility by all known occurring species, including the less-maneuverable T. brasiliensis that is known to form large colonies in the park. Laguna de Juan Garcia is also important as a more permanent water source during drought conditions in the earlier part of the spring and summer, as observed in 2011.