Although bats are frequently admitted to rescue centres — mainly as orphans — very little information is available on their survival after release. Our study answered the following questions: i) do hand-reared bats survive over a short time; ii) which activities and habitat selection do they exhibit; iii) are bats loyal to the release area; and iv) are they able to join local colonies? We radio-tracked 21 hand-reared Pipistrellus kuhlii over a two-year period released on a site that differed from that where they were rescued. At the study site they were provided with the same bat boxes used in the rehabilitation room. Nineteen bats were confirmed to survive, stay in the area and actively forage over 4-14 days. Fourteen day roosts in buildings (nine of which hosted a local colony) were used by 12 subjects. Bats travelled less than 5 km in total each night; their most frequent activity was night roosting, followed by foraging and commuting. We recorded typical foraging behaviour, including hunting around street lamps at sites exploited by many conspecifics. A comparison of habitats available within individual home ranges with those within the study area showed that urban areas, riparian vegetation and farmland were equally important and preferred to woodland. When the foraging time spent in each habitat was compared with habitat composition within individual home ranges or within the study area, urban sites were preferred for foraging over all other habitats, followed by farmland and woodland and finally riparian vegetation. Overall, we showed that hand-raised orphaned P. kuhlii may readily adapt to environments they are not familiar with, exhibit a high short-term survival and select key resources in the release area, provided appropriate rehabilitation and training techniques are adopted.

Newly established populations of endangered species can help mitigate declines elsewhere and can be a valuable genetic reservoir. When these populations are located within anthropogenic habitats, they may also help mitigate the potential biodiversity loss created by urbanization. The Red-crowned Amazon Amazona viridigenalis is an endangered species that has become naturalized in multiple urban areas throughout the United States and Mexico, and these populations may currently outnumber the population within their historical habitat. While these urban populations may hold the majority of this endangered species, very few studies have analyzed the status and trends of this species, or of threatened parrots in general, in urban areas. Our study focuses on an urban Red-crowned Amazon population in the Lower Rio Grande Valley (LRGV) of Texas: the only parrot population currently recognized as native to the United States. To determine a timeline of Red-crowned Amazon arrival and growth in the LRGV, we reviewed published literature and online citizen science databases. To quantify current population levels and trends, we conducted 412 surveys at all known roost sites throughout the LRGV from January 2016 through April 2019. We also quantified the ratio of adult and juvenile parrots at roosts. Our data suggest the species has been present in the LRGV consistently since the 1970s and showed rapid growth from the mid-1990s through roughly 2016. Roost counts suggest there is currently a minimum LRGV population of about 680 and the population has been relatively stable over the last 3.5 years. Productivity averaged 19% over three breeding seasons, suggesting successful internal reproduction. This study provides important baseline information for the management and conservation of Red-crowned Amazons in the region and provides a valuable timeline on the beginnings and trends of this recently established urban population of Amazona parrot.

For parasites in natural systems, the most common pattern of spatial distribution is aggregation among hosts. The main causes of such aggregation are variable exposure of hosts to parasites and heterogeneity in host susceptibility. The objective of this study was to determine if there are differences in the aggregation pattern of two species of ectoparasitic flies between the Pantanal and Cerrado regions of Brazil on the bat Artibeus planirostris. We collected the ectoparasites from bats captured between 2002 and 2017 with mist nets in 21 sites in the Pantanal and 15 sites in the surrounding plateaus. The results showed that the aggregation of ectoparasitic flies in Pantanal was more pronounced than in Cerrado. The discrepancy aggregation index (D) of the bat fly Megistopoda aranea was 0.877 in Pantanal and 0.724 in Cerrado. The D values of Aspidoptera phyllostomatis was even higher, with 0.916 and 0.848 in the Pantanal and Cerrado, respectively. Differences in the shelters used may be the main factor shaping variation in aggregation, since the Pantanal does not have rock formations, with only foliage, crowns and hollow tree trunks. These differences likely affect host exposure to the parasites, leading to an increase in parasite aggregation.

Nutrient subsidies from one ecosystem to another serve a critical link among ecosystems. The transfer of materials across the terrestrial-to-marine boundary is considered to be driven by hydrological connectivity, but animal movement can provide another pathway for nutrient transfers. In two separate studies we assessed the role mammals (bats and kangaroos) play in alleviating nutrient limitation in mangrove forests in Australia. At Lizard Island, we measured tree growth and foliar elemental and isotopic composition of trees growing within and outside a large flying fox roost. In Western Australia, we measured foliar elemental and isotopic composition of trees within two forests frequented by kangaroos that feed in spinifex grasslands and shelter in the shade of the mangroves. We compared those with mangroves from adjacent forests that are not frequented by kangaroos. We show that at both locations, the mangrove forest receives terrestrial nutrient subsidies through animal movement. At Lizard Island dominant mangrove species were significantly enriched in nitrogen within the bat roost, as evidenced by higher foliar N concentrations (by up to 150%), N:P and N:C ratios in trees within the roost compared with trees outside the roost. The isotopic signature of foliar N was significantly enriched in 15N by 1–3‰ within the roost, further suggesting that the source of the N enrichment was the bat roost. Growth rates of mangroves within the roost were nearly six times higher than trees outside the roost. In the arid coast of Western Australia, we show elevated foliar 15N abundance of up to 3‰ in mangroves where kangaroos shelter relative to trees where they do not. Thus, this study presents two examples for mammalian herbivore mediated localized transport of nutrients from terrestrial to marine ecosystems, consequently affecting mangrove tree growth, productivity and forest structure.

Estimations of the population sizes of threatened species are fundamental for conservation. The current estimate of the population of the Andean condor Vultur gryphus is based on limited local counts. Simultaneous censuses of 10 condor communal roosts were therefore conducted during 2006–2008 in north-west Patagonia, Argentina, to obtain a minimum population number, to estimate the size of the local population, and to describe use of the roosts by season and age classes. I fitted the data to two asymptotic models to calculate the population of condors as a function of the number of communal roosts surveyed. In an area of c. 6,300 km2 I obtained a minimum population size of 246 individuals by direct observation, and a population estimate of 296 condors (range 260–332) by applying the models. This population, the largest known of this species, comprises 68.5% adults and 31.5% immatures. Condors had large aggregations in some communal roosts and used the area seasonally, increasing in numbers from autumn to spring and decreasing in summer. Long-term monitoring of communal roosts across the Andean condor’s range is essential for the monitoring of this rare and vulnerable species.

Bat populations in China appear to have decreased considerably in the last 30 years. Four reasons may have been responsible: (1) Cave exploitation for tourism has changed the atmosphere and temperature in caves, disturbing bats directly. (2) Extensive pesticide use has resulted in bioaccumulation in bats, reducing their survival. (3) Many old buildings were demolished during urbanization, reducing the availability of suitable roost sites. (4) People often include bats in their diet, and bats are served in restaurants. We make recommendations for improving bat conservation in China. Education programmes about bat conservation should be provided for adults and schoolchildren, and laws for protecting bats need to be enacted and enforced. The roosting sites of bats should be protected comprehensively, and pesticide use should be regulated.

Most regions of the world support moth species that use caves as diurnal roosts and/or as overwintering and mating sites. Although subterranean roosts are often also occupied by insectivorous bats, nothing is known about moth–bat interaction at these sites. The frequency of cohabitation and the dynamics of moth–bat interaction at roosts were examined during surveys at 30 known bat roosts in eastern Australia; 15 disused mines and 15 natural caves. Moths and bats cohabited in 20 roosts (67%); however, only two species of eared moths, Speiredonia spectans and S. mutabilis (Noctuidae), were observed. These large (wingspan up to 75 mm) species show a classic escape response to ultrasound. Moths used roosts occupied by bats with both frequency modulated (FM) (four species) and constant frequency (CF) (two species) echolocation calls. Signal frequencies of these bats had ranges of 23–25 and 44–71 kHz. Moths were absent from roosts occupied by high-frequency (>140 kHz) CF bats. Predator–prey interaction was assessed by studying a sub-sample of six roosts occupied by S. spectans and the horseshoe bat Rhinolophus megaphyllus. Speiredonia spectans and R. megaphyllus cohabited roosts throughout the year. Bats captured and consumed moths in these roosts. The numbers of moth wings on the floor of roosts were counted to assess rates of predation. Bats consumed 209 moths at the six roosts over a 12-month period, representing 19% of the moth population at the start of the study. The study establishes that moth–bat cohabitation of roosts is relatively common in eastern Australia and that bats do capture moths in these sites. Bat predation seems to be a significant source of mortality of moths that occupy subterranean roosts.

Acoustic monitoring and radio-tracking were used to study the nocturnal activity of adult female Indiana bats Myotis sodalis at a maternity site in Michigan, U.S.A. Pregnant bats did not use the day roost at night, but lactating females returned 2–4 times/night for 32±7 (SE) min/visit, presumably to feed their young. Both pregnant and lactating females night roosted as solitary individuals in trees within their foraging areas; night roosting occurred 0–6 times/night for 14±1 min each time. Bats foraged for most of the night, with the total duration of flight equalling 375±16 min/night. The bats used 13 different foraging areas that were located 0.5–4.2 km from the day roost. Bats did not fly over open fields but travelled along wooded corridors, even though such behaviour increased commuting distance by 55±11%. Current models of habitat suitability for this endangered species should be modified, taking into account the use of wooded commuting corridors and the large home range of these bats.

Use of roosts by the golden-tipped bat Kerivoula papuensis was investigated principally in the Richmond Range National Park, north-eastern New South Wales and Mt Baldy State Forest in north-eastern Queensland, Australia. Roosts were located primarily using radiotelemetry; although others were found by light tagging, visual location and nest searching techniques. In the main study site in the Richmond Range a total of 54 K. papuensis diurnal roosts were located, 96.5% occurring in the suspended nests of the yellow-throated scrubwren Sericornis citreogularis (Pardalotidae) (93%) and the brown gerygone Gerygone mouki (Pardalotidae) (3.5%). At Mt Baldy, K. papuensis displayed greater variation in day roost selection, although 73% were in S. citreogularis nests. In both sites, day roosts were confined to the lower stratum of rainforest with a small proportion in eucalypt tall open forest with a rainforest subcanopy. Diurnal roosts were located at distances varying from 20 to 1200 m to the nearest major vegetation ecotone, ranging from along watercourses upslope to ridgelines. Diurnal roosts were predominantly occupied by single bats, with a maximum group size of eight individuals. All roosts in hanging nests were modified by the presence of a basal hole. Strong circumstantial evidence was provided that K. papuensis modified these roost structures in a manner allied to tent-making bats. A single maternity roost was located in the hollow of a rainforest canopy tree, Flindersia australis (Rutaceae).

At one nursery roost of Leisler's bat Nyctalus leisleri, the first bat often, and over half of the colony exceptionally, left before sunset. Departure was earlier during the period of lactation, when energy demands were highest. Consequently emergence data had to be standardized to allow for this before investigating possible associations with light intensity and meteorological factors. The importance of such standardization in general is emphasized. Emergence was earlier on overcast nights and was delayed with increased light intensity. The bats in a neighbouring roost, from which fewer data were obtained, also left earlier on overcast evenings, but departure was generally later than in the first roost, and there was no evidence of its being earlier during lactation. These differences between the roosts may be at least partially explained by the difference in size of the exit holes. At both roosts departure was mainly as a series of outbursts, and this was more marked during the first half of emergence. Rate of emergence increased with colony size. It was unusual for the first bat to leave more than 30 min, or for any bat to leave over 60 min, after sunset. Heavy rain inhibited or disrupted emergence.