NOTES ON AN ARTIFICIAL ROOST OF Myotis albescens (CHIROPTERA, VESPERTILIONIDAE) IN SOUTHEASTERN BRAZIL

Myotis albescens has a wide distribution, occurring from southern Mexico to central Argentina and Uruguay, where it is usually caught near streams or flooded areas. M. albescens roosts during the day in cavities such as hollow logs, rock cavities, and buildings. Here, we describe a group of M. albescens roosting in a highway underpass in an Atlantic Forest area in Rancharia, southeastern Brazil. The group was found inside a culvert with a shallow stream passing through it. The animals left the roost and were mist-netted in the first hours of the night. The M. albescens group was composed of 18 individuals, eleven males and seven females. In October, all males had descended testes and two females were pregnant, as confirmed by abdominal palpation. Morphological characters of the specimens fell in the known variation for the species. Our data show that highway underpasses can be important day roosts for bats, especially if riparian areas are preserved

Do bats use guano and urine stains to find new roosts? Tests with three group-living bats

Many animals use social cues to find refuges. Bats can find roosts using the echolocation and social calls of conspecifics, but they might also use scent cues, a possibility which is less studied. The entrances of bat roosts are often marked by guano and urine, providing possible scent cues. We conducted eight experiments to test whether bats use the scent of guano and urine to find potential roosts. In field experiments, we tested if Molossus molossus (velvety free-tailed bats) in Panama and Eptesicus fuscus (big brown bats) in Ohio would investigate artificial roost boxes that were scented with guano and urine more often than a paired unscented control. We did not detect any difference in flights near the scented versus unscented roosts, and we detected only one entrance into any artificial roost (scented). In six captive experiments, we tested for the attraction of Desmodus rotundus (common vampire bats) and Molossus molossus to areas scented with guano and urine, under several conditions. Results were mixed, but overall suggested that the scent of guano and urine does not act as a strong lure for the tested bat species. We suggest that further tests of olfaction-based roost choice in bats should manipulate existing scent cues on familiar roosts.

An artificial site provides valuable additional habitat to migratory shorebirds in a tropical harbour

Migratory shorebirds are declining in all transequatorial flyways, most rapidly in the East Asian–Australasian Flyway. Population trends for shorebirds have been derived at a flyway and continental scale, but changes at the local scale are less well understood. Here we compare trends in migratory shorebird populations using natural and artificial roost sites within a tropical harbour, examine possible drivers of change, and identify appropriate conservation management responses. Counts of 19 migratory shorebird species from 2010 and 2018 showed that total abundance increased at an average annual rate of 3.3% (95% CI=1.3–5.4%, P=0.001) across five natural roost sites. This was driven largely by increases in great knot, with most other species declining. At an artificial site in an adjacent shorebird area, total abundance increased at an average annual rate of 14.5% (95% CI=10.5–18.6%, P ≤ 0.000), with few species declining. These results suggest that there is a need to include both natural and artificial sites within shorebird conservation and management planning and that trends in different species can be driven by a combination of local and external drivers.

The use of bat houses as day roosts in macadamia orchards, South Africa

The loss of roost sites is one of the major drivers of the worldwide decline in bat populations and roost site preferences, either natural or artificially provided, are not well known for African bat species specifically. In this study we focus on the preference for different artificial roost sites by insectivorous bats in macadamia orchards in northern South Africa. From June 2016 to July 2017 we monitored 31 bat houses, mounted on poles in six macadamia orchards, for presence of bats or other occupants. Twenty-one multi-chambered bat houses of three different designs were erected in sets of three. Additionally, five Rocket boxes, four bat houses in sets of two (painted black and white) and one colony bat house were erected. Bats were counted and visually identified to family or species level. From December 2016 to the end of March 2017 iButtons were installed to record and analyze temperature variation within one set of three bat houses. We related the occupancy of bat houses to the different types of houses and the environmental variables: distance to water, altitude and height of the bat houses above the ground. Overall bat house occupancy was significantly higher in the central bat house, in the set of three, and the black bat house, in the set of two. Mean temperatures differed between houses in the set of three with the central bat house having a significantly higher mean temperature than the houses flanking it. Our study might confirm previous assumptions that the microclimate of bat houses appears to be an important factor influencing occupancy. In conclusion, from the different bat houses tested in this study the designs we assume the warmest and best insulated attracted the most bats. Further research is needed on the preferred microclimate of different bat species, co-habitation within bat houses and the potential importance of altitude and distance to water. Our study provided little variation in both altitude and the distance to water.

Use of roof as roost of Eumops perotis (Molossidae: Chiroptera) in southeast Brazil

ABSTRACT The bat Eumops perotis (Schinz, 1821) is broadly distributed in the Americas. Studies on its biology are still scarce and the few studies available are relatively outdated. In the present study, we describe the biology of Eumops perotis in an artificial roost in the municipality of Pindorama, State of São Paulo, southeastern Brazil, which was monitored for 12 months. We captured 50 individuals; 43 adults (34 males and 9 females) and seven juveniles (three males and four females). Nineteen adults were recaptured throughout the year (15 males and four females) during samplings. Males were ~33% heavier than females. Males remained in the roost throughout the year, while females were absent in June, July, and August. The presence of males with scrotal testes and pregnant females from July to November and the presence of pregnant females and pups from February to April suggest monoestry for this colony. Inside the roost, the behavior of E. perotis was similar to other molossid bats (e.g. contact posture, formation of groups, and presence of isolated males). During winter, the individuals of this colony consumed mostly coleopterans, but their diet also included orthopterans and lepidopterans, mainly in the summer. Therefore, this study contributes to increase the knowledge of the natural history of this species in the Neotropical region.

New records on the use of man-made constructions as diurnal roosts by bats from the southern Amazon in central Brazil

ABSTRACT Roosts are a key part of bat species' life stories. Information on roost use enables us to understand the biological processes underlying bat ecology and is crucial with regard to the natural-roost loss and environmental pressures related to habitat destruction that has been considered as a threat affecting bat conservation. The aim of this study was to collect new data on the diurnal artificial-roost use by bats in a landscape from the southern Amazon. We observed bat species roosting at an abandoned house in a highly fragmented ecotone between the Amazon and Cerrado biomes. We observed one Trachops cirrhosus individual roosting in physical contact with one Phyllostomus hastatus. One year later, we noticed a compositional change at this roost, in which we found a large colony of Pteronotus parnellii. These findings may shed light on the potential flexibility of the roosting requirements of these species in such landscapes. Moreover, this is one of the first records of the use of human constructions by P. parnelli in such fragmented landscapes, a bat species that until recently was thought of as being associated only with well-preserved natural roosts.

Research priorities for the Pilbara leaf-nosed bat (Rhinonicteris aurantia Pilbara form)

Significant biodiversity offset funds have been allocated towards conservation research on threatened species as part of the environmental approvals process for resource development in the Pilbara region of Western Australia. One of these species is the Pilbara leaf-nosed bat (Rhinonicteris aurantia Pilbara form), which is entirely reliant on roosting in a limited number of caves and disused mines, many of which exist in the mineral-bearing strata that are the focus of mining activity. A research agenda for the Pilbara leaf-nosed bat was developed during a workshop attended by scientists, environmental consultants and mining industry representatives. Five research priorities were identified: (1) collate existing data contained within unpublished environmental surveys; (2) clarify and better characterise the number and distribution of day roosts; (3) better understand habitat requirements, particularly foraging habitat, and the movement of bats between roosts; (4) provide more robust estimates of total population and colony size, and improve understanding of social behaviour; and (5) investigate appropriate buffers in a range of mining contexts and protocols for artificial roost construction. Meta-analysis of current data, confirmation of potential day roosts, and long-term monitoring of activity patterns would rapidly increase our knowledge of the Pilbara leaf-nosed bat to enable effective conservation actions.