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829 result(s) for "roost"
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Correlations between personality traits and roosting behaviours suggest a behavioural syndrome in little brown bats
Abstract Behavioural syndromes are composed of correlated suites of personality traits and can include traits related to the behaviour and ecology of free-ranging animals. We used captive little brown bats (Myotis lucifugus) to test the hypothesis that behaviours measured in standardized tests reflect personality traits and form behavioural syndromes with roosting behaviours. We predicted: (1) measured behaviours would be repeatable; (2) personality traits and roosting behaviours would form behavioural syndromes; and (3) individuals with similar personality scores would associate more strongly. We observed repeatability for some traits and evidence of behavioural syndromes. Activity was strongly repeatable across time and contexts. More central individuals roosted in larger groups, while individuals with high roost-fidelity roosted in larger groups. Individuals with similar activity scores were also more likely to associate in day roosts, suggesting some behavioural assortment. Our results have implications for how behavioural variation might influence transmission of white-nose syndrome.
Roost sites of chimney swift (Chaetura pelagica) form large‐scale spatial networks
Several biodiversity‐centered metrics exist to quantify the importance of landscape and habitat features for conservation efforts. However, for species whose habitat use is not quantified by these metrics, such as those in urban areas, we need a method to best identify features for targeted conservation efforts. We investigated the use of social network analysis (SNA) to identify and quantify these critical habitat features. We used SNA to identify network existence in chimney swift (Chaetura pelagica) roost usage, quantify the importance of each roost site, and evaluate the impact of the loss of key sites. We identified a network consisting of ten chimney swift roosts in southern Nova Scotia, Canada, and found that 76% of swifts used more than one roost throughout the breeding season. We also isolated three key (most connected) roost sites. We evaluated the effect of loss of these key sites on the network by using a Wilcoxon‐Pratt signed‐rank test and by analyzing the structure of the subsequent network. We found that connections between roosts and the structure of the network were significantly affected by the loss of these key sites. Our results show that SNA is a valuable tool that can identify key sites for targeted conservation efforts for species that may not be included in conservation efforts focused purely on biodiversity. Social network analysis (SNA) reveals that roost sites separated by hundreds of kilometers form a spatial network for Chimney Swifts, a species long believed to have fidelity to single roosts. SNA has never been applied to the spatial ecology of wildlife in this way and promises to aid in identifying sites in greatest need of conservation.
Population dynamics of little brown bats (Myotis lucifugus) at summer roosts: Apparent survival, fidelity, abundance, and the influence of winter conditions
White‐nose syndrome (WNS) has caused the death of millions of bats, but the impacts have been more difficult to identify in western North America. Understanding how WNS, or other threats, impacts western bats may require monitoring other roosts, such as maternity roosts and night roosts, where bats aggregate in large numbers. Little brown bats (Myotis lucifugus) are experiencing some of the greatest declines from WNS. Estimating survival and understanding population dynamics can provide valuable data for assessing population declines and informing conservation efforts. We conducted a 5‐year mark–recapture study of two M. lucifugus roosts in Colorado. We used the robust design model to estimate apparent survival, fidelity, and abundance to understand population dynamics, and environmental covariates to understand how summer and winter weather conditions impact adult female survival. We compared the fidelity and capture probability of M. lucifugus between colonies to understand how bats use such roosts. Overwinter survival increased with the number of days with temperatures below freezing (β > 0.100, SE = 0.003) and decreased with the number of days with snow cover (β < −0.40, SE < 0.13). Adult female fidelity was higher at one maternity roost than the other. Overwinter and oversummer adult female survival was high (>0.90), and based on survival estimates and fungal‐swabbing results, we believe these populations have yet to experience WNS. Recapture of M. lucifugus using antennas that continuously read passive integrated transponder tags allows rigorous estimation of bat population parameters that can elucidate trends in abundance and changes in survival. Monitoring populations at summer roosts can provide unique population ecology data that monitoring hibernacula alone may not. Because few adult males are captured at maternity colonies, and juvenile males have low fidelity, additional effort should focus on understanding male M. lucifugus population dynamics. This is a mark–recapture analysis of little brown bat populations at two summer roosts to understand abundance, survival, and fidelity. At the maternity colony, adult females showed high survival and fidelity, while another colony that may serve as a maternity, day, and night roosts had lower estimates of fidelity.
Roosting behaviour of greater noctule bats ( Nyctalus lasiopterus ) in forests in Spain and implications for species conservation and forest management
The greater noctule ( Nyctalus lasiopterus ) is a threatened tree-roosting bat species with a fragmented distribution, possibly due to limited roosting habitat. Deforestation, tree disease and climate change are reducing forest and roost availability. Effective conservation action and forest management require detailed knowledge of the bats’ roosting behaviour and requirements, which is lacking for this species, particularly in southern European forests. We studied the roosting behaviour of 25 radio-tagged females from three maternity colonies in the forest and the urban environment, as well as 11 males from a forest mating site in Spain. We found similar behaviour and roost group sizes (14–18 individuals) for both sexes in the forest, where bats mainly roosted in woodpecker holes in larger trees of abundant tree species. Bats switched between many roosts (0.2–0.3 roosts d −1 ) across large forest areas (up to 1300 ha). At the urban site, females rarely switched between four exotic palm tree roosts, with roost group sizes reaching 144 individuals. Despite its adaptability, N. lasiopterus may require large forest roosting areas that provide a greater roost diversity, aiding thermoregulation and predator avoidance. Conservation efforts should focus on protecting large forests with high woodpecker abundance to ensure roost availability, supported by artificial bat roosts.
Thermally unstable roosts influence winter torpor patterns in a threatened bat species
Abstract Many hibernating bats in thermally stable, subterranean roosts have experienced precipitous declines from white-nose syndrome (WNS). However, some WNS-affected species also use thermally unstable roosts during winter that may impact their torpor patterns and WNS susceptibility. From November to March 2017–19, we used temperature-sensitive transmitters to document winter torpor patterns of tricolored bats (Perimyotis subflavus) using thermally unstable roosts in the upper Coastal Plain of South Carolina. Daily mean roost temperature was 12.9 ± 4.9°C SD in bridges and 11.0 ± 4.6°C in accessible cavities with daily fluctuations of 4.8 ± 2°C in bridges and 4.0 ± 1.9°C in accessible cavities and maximum fluctuations of 13.8 and 10.5°C, respectively. Mean torpor bout duration was 2.7 ± 2.8 days and was negatively related to ambient temperature and positively related to precipitation. Bats maintained non-random arousal patterns focused near dusk and were active on 33.6% of tracked days. Fifty-one percent of arousals contained passive rewarming. Normothermic bout duration, general activity and activity away from the roost were positively related to ambient temperature, and activity away from the roost was negatively related to barometric pressure. Our results suggest ambient weather conditions influence winter torpor patterns of tricolored bats using thermally unstable roosts. Short torpor bout durations and potential nighttime foraging during winter by tricolored bats in thermally unstable roosts contrasts with behaviors of tricolored bats in thermally stable roosts. Therefore, tricolored bat using thermally unstable roosts may be less susceptible to WNS. More broadly, these results highlight the importance of understanding the effect of roost thermal stability on winter torpor patterns and the physiological flexibility of broadly distributed hibernating species. Many hibernating bats have experienced precipitous declines from white-nose syndrome (WNS). However, some WNS-affected species use roosts which may impact their winter behavior (e.g., activity and torpor patterns) and WNS susceptibility. Our results suggest tri-colored bats using thermally unstable roosts may be less susceptible to WNS because of their winter behavior and roost characteristics.
Winter roosting ecology of tricolored bats (Perimyotis subflavus) in trees and bridges
Tricolored bats (Perimyotis subflavus) that roost in subterranean hibernacula have experienced precipitous declines from white-nose syndrome (WNS); however, understudied populations also use during winter non-subterranean roosts such as tree cavities, bridges, and foliage. Our objectives were to determine winter roost use by tricolored bats in an area devoid of subterranean roosts, determine roost microclimates to relate them to growth requirements of the fungal causal agent of WNS, and determine habitat factors influencing winter tree selection. From November to March 2017–2019, we used radiotelemetry to track 15 bats to their day roosts in the upper Coastal Plain of South Carolina and recorded microclimates in accessible tree cavities and bridges. We also characterized habitat and tree characteristics of 24 used trees and 153 random, available trees and used discrete choice models to determine selection. Roost structures included I-beam bridges, cavities in live trees, and foliage. Bridges were warmer and less humid than cavities. Roost temperatures often were amenable to fungal growth (< 19.5°C) but fluctuated widely depending on ambient temperatures. Bats used bridges on colder days (8.7°C ± 5.0 SD) and trees on warmer days (11.3°C ± 5.4). Bats selected low-decay trees closer to streams in areas with high canopy closure and cavity abundance. Bats also appeared to favor hardwood forests and avoid pine forests. Our results suggest that access to multiple roost microclimates might be important for tricolored bats during winter, and forest management practices that retain live trees near streams and foster cavity formation in hardwood forests likely will benefit this species. Our results also suggest tricolored bats using bridge and tree roosts might be less susceptible to WNS than bats using subterranean hibernaculum roosts. Thus, forests in areas without subterranean hibernacula in the southeastern United States that support bats during winter might represent important refugia from WNS for multiple species.
Year-round differences in the use of roosting sites in an endangered vulture reveal gaps in protected areas coverage
Protected areas (PAs) are one of the main tools used to promote species persistence and biodiversity conservation worldwide. Assessing the use and effectivity of protected areas (e.g., PAs and Nature 2000 network), by using forefront methods such as GPS technology, has grown in importance over the last decades due to the advantages these methods offer. In the case of birds, the use of these technologies provides vital information to identify key areas and habitats throughout their movement ecology and has become a particularly useful tool to identify key areas for threatened species of birds that should be declared legally protected. The Egyptian vulture Neophron percnopterus is an Endangered social scavenger species. Though roosts are key for the species, the protection is mainly centred on nesting places and not at roosting sites, most of which are unknown. We used year-round movement data from 11 Egyptian vultures to identify and analyse the use of their night roosts according to the frequency of use and we assessed their protection. We identified 50 ‘multi-use roosts’, 80 ‘occasional roosts’ and 339 ‘one-night roosts’. PAs cover 12.5% of the identified roosting sites, while Nature 2000 network sites give cover to only 20% of the identified night roosts under a legal protection figure. However, Important Biodiversity Areas (IBAs), a network without a legal figure, cover 71% of these roosts identified. We thus encourage managers and conservation practitioners to use tracking technologies to identify vital areas for threatened species and assess their protection in combination with fieldwork.
Roosting ecology of Gould's wild turkeys in southeastern Arizona
Availability of suitable roosting sites influences distribution of wild turkeys (Meleagris gallopavo) across the landscape. In semi-arid environments, roosts are limited to riparian corridors capable of supporting trees large enough to provide suitable roost sites. Gould's wild turkeys (M. g. mexicana) are spatially restricted to mountainous semi-arid areas of southwestern United States and Mexico, and information on their distribution and habitat use is limited. We evaluated roost site selection and fidelity of Gould's wild turkeys relative to environmental gradients and forested land cover during 2016–2017 in southeastern Arizona, USA. We monitored 51 global positioning system (GPS)-tagged individuals and collected 7,954 night roost locations. We quantified specific roost site characteristics at 274 unique roost locations. Gould's wild turkeys roosted in forested communities dominated by mature pine (Pinus spp.) and oak (Quercus spp.), and exhibited substantive roost site fidelity. Roost sites were selected at moderate elevations (range = 1,254–2,894 m), and were predominately on north-facing slopes with slight incline (< 11°), suggesting little plasticity in selection of roost sites. Conserving habitat with topography and vegetative structure similar to those described in our study is likely to improve ongoing restoration and management of Gould's wild turkeys.
The avian “hibernation” enigma
Compared to mammals, there are relatively few studies examining heterothermy in birds. In 13 bird families known to contain heterothermic species, the common poorwill (Phalaenoptilus nuttallii) is the only species that ostensibly hibernates. We used temperature-sensitive radio-transmitters to collect roost and skin temperature (Tskin) data, and winter roost preferences for free-ranging poorwills in southern Arizona. Further, to determine the effect of passive rewarming on torpor bout duration and active rewarming (i.e., the use of metabolic heat to increase Tskin), we experimentally shaded seven birds during winter to prevent them from passively rewarming via solar radiation. Poorwills selected winter roosts that were open to the south or southwest, facilitating passive solar warming in the late afternoon. Shaded birds actively rewarmed following at least 3 days of continuous torpor. Average torpor bout duration by shaded birds was 122 h and ranged from 91 to 164 h. Active rewarming by shaded birds occurred on significantly warmer days than those when poorwills remained torpid. One shaded bird remained inactive for 45 days, during which it spontaneously rewarmed actively on eight occasions. Our findings show that during winter poorwills exhibit physiological patterns and active rewarming similar to hibernating mammals.