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Haddaway L, McGuire LP. Seasonal and Nightly Activity Patterns of Migrating Silver-Haired Bats (Lasionycteris noctivagans) Compared to Non-Migrating Big Brown Bats (Eptesicus fuscus) at a Fall Migration Stopover Site. ACTA CHIROPTEROLOGICA 2022. [DOI: 10.3161/15081109acc2022.24.1.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Lucas Haddaway
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
| | - Liam P. McGuire
- Department of Biology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L 3G1, Canada
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López-Baucells A, Yoh N, Rocha R, Bobrowiec PED, Palmeirim JM, Meyer CFJ. Optimizing bat bioacoustic surveys in human-modified Neotropical landscapes. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02366. [PMID: 33938592 DOI: 10.1002/eap.2366] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
During the last decades, the use of bioacoustics as a non-invasive and cost-effective sampling method has greatly increased worldwide. For bats, acoustic surveys have long been known to complement traditional mist-netting, however, appropriate protocol guidelines are still lacking for tropical regions. Establishing the minimum sampling effort needed to detect ecological changes in bat assemblages (e.g., activity, composition, and richness) is crucial in view of workload and project cost constraints, and because detecting such changes must be reliable enough to support effective conservation management. Using one of the most comprehensive tropical bat acoustic data sets, collected in the Amazon, we assessed the minimum survey effort required to accurately assess the completeness of assemblage inventories and habitat selection in fragmented forest landscapes for aerial insectivorous bats. We evaluated a combination of 20 different temporal sampling schemes, which differed regarding number of hours per night, number of nights per site, and sampling only during the wet or dry season, or both. This was assessed under two different landscape scenarios: in primary forest fragments embedded in a matrix of secondary forest and in the same forest fragments, but after they had been re-isolated through clearing of the secondary forest. We found that the sampling effort required to achieve 90% inventory completeness varied considerably depending on the research aim and the landscape scenario evaluated, averaging ~80 and 10 nights before and after fragment re-isolation, respectively. Recording for more than 4 h per night did not result in a substantial reduction in the required number of sampling nights. Regarding the effects of habitat selection, except for assemblage composition, bat responses in terms of richness, diversity, and activity were similar across all sampling schemes after fragment re-isolation. However, before re-isolation, a minimum of four to six sampling hours per night after dusk and three to five nights of sampling per site were needed to detect significant effects that could otherwise go unnoticed. Based on our results, we propose guidelines that will aid to optimize sampling protocols for bat acoustic surveys in the Neotropics.
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Affiliation(s)
- Adrià López-Baucells
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, 1749-016, Portugal
- Natural Sciences Museum of Granollers, Av/Francesc Macià 51, Granollers, Catalonia, 08402, Spain
- Biological Dynamics of Forest Fragments Project (PDBFF), National Institute for Amazonian Research and Smithsonian Tropical Research Institute, Manaus, AM, 69011-970, Brazil
| | - Natalie Yoh
- Ecosystems and Environment Research Centre (EERC), School of Science, Engineering and Environment, University of Salford, Salford, M5 4WT, United Kingdom
- Durrell Institute of Conservation & Ecology (DICE), University of Kent, Canterbury, CT2 7NZ, United Kingdom
| | - Ricardo Rocha
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, 1749-016, Portugal
- Biological Dynamics of Forest Fragments Project (PDBFF), National Institute for Amazonian Research and Smithsonian Tropical Research Institute, Manaus, AM, 69011-970, Brazil
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, 4485-661, Portugal
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, Institute of Agronomy, University of Lisbon, Lisbon, 1349-017, Portugal
| | - Paulo E D Bobrowiec
- Biological Dynamics of Forest Fragments Project (PDBFF), National Institute for Amazonian Research and Smithsonian Tropical Research Institute, Manaus, AM, 69011-970, Brazil
| | - Jorge M Palmeirim
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, 1749-016, Portugal
| | - Christoph F J Meyer
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Lisbon, 1749-016, Portugal
- Biological Dynamics of Forest Fragments Project (PDBFF), National Institute for Amazonian Research and Smithsonian Tropical Research Institute, Manaus, AM, 69011-970, Brazil
- Ecosystems and Environment Research Centre (EERC), School of Science, Engineering and Environment, University of Salford, Salford, M5 4WT, United Kingdom
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Mayberry HW, McMillan MR, Chochinov AV, Hinds JC, Ratcliffe JM. Potential foraging niche release in insectivorous bat species relatively unaffected by white-nose syndrome? CAN J ZOOL 2020. [DOI: 10.1139/cjz-2019-0231] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
White-nose syndrome (WNS) has rendered four of Ontario’s species endangered, while leaving the other four species relatively unaffected. The causes and extent of the declines have been widely studied. The influence on remaining bat species has not. Comparing acoustic data recorded ∼10 years apart, we evaluated how species in southeastern Ontario, Canada, use different foraging habitats pre- and post-WNS detection. We observed activity declines in now-endangered species over open fields (small-footed myotis, Myotis leibii (Audubon and Bachman, 1842); little brown bat, Myotis lucifugus (Le Conte, 1831); northern myotis, Myotis septentrionalis (Trouessart, 1897); tricolored bat, Perimyotis subflavus (F. Cuvier, 1832)) and speculate that the reduction of the once most common species (M. lucifugus) may have resulted in other species searching for prey in habitat once dominated by M. lucifugus. That is, these changes may have allowed greater presence in open field and clutter or edge environments by the big brown bat (Eptesicus fuscus (Palisot de Beauvois, 1796)) and three migratory species (silver-haired bat, Lasionycteris noctivagans (Le Conte, 1831); red bat, Lasiurus borealis (Müller, 1776); hoary bat, Lasiurus cinereus (Palisot de Beauvois, 1796)). However, our results also suggest that (i) while the decline of most resident bat species due to WNS may have relaxed competition for relatively unaffected species in some, but not all habitats, that (ii) sensory and biomechanical constraints may limit prey exploitation by these less-affected bat species in these habitats.
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Affiliation(s)
- Heather W. Mayberry
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada
| | - M. Reese McMillan
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada
| | - A. Vikram Chochinov
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
- Department of Earth Sciences, University of Toronto, 22 Russell Street, Toronto, ON M5S 3B1, Canada
| | - Joshua C. Hinds
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
- Department of Psychology, Neuroscience, and Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - John M. Ratcliffe
- Department of Biology, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2, Canada
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Baloun DE, Hobson KA, Guglielmo CG. Temporal patterns of foraging by silver-haired bats during migratory stopover revealed by isotopic analyses (δ 13C) of breath CO 2. Oecologia 2020; 193:67-75. [PMID: 32306117 DOI: 10.1007/s00442-020-04650-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 04/08/2020] [Indexed: 11/26/2022]
Abstract
The extent to which migratory bats forage at stopover sites or while in migratory flight is poorly understood. Endogenous fat stores have lower δ13C values relative to the dietary substrates from which they were synthesized, and so, the fed versus fasted state of bats should be discernable by comparing their breath δ13C at capture to that after a known period of fasting. We captured silver-haired bats (Lasionycteris noctivagans) at a stopover site at Long Point, Ontario, Canada, during spring and fall migration. We collected breath samples at capture and after fasting in captivity for 12 h, providing a fasted-state δ13C value corresponding to metabolism of fat stores. We also collected and weighed fecal pellets produced while in captivity. Breath δ13C values at capture were positively correlated with mass of feces produced. During spring migration, δ13C values of breath CO2 at capture were low and similar to fasting values, but increased with date consistent with increased foraging at stopover and reliance on exogenous dietary nutrients as the season progressed. The opposite temporal pattern was found during fall migration. Our findings suggest that bats forage during migratory stopover when environmental conditions permit despite potential time trade-offs between feeding and travel, and the energy savings resulting from torpor during roosting. This study provides insight into the eco-physiology of bat migration and shows the importance of foraging habitat for migratory bats.
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Affiliation(s)
- Dylan E Baloun
- Department of Biology and Advanced Facility for Avian Research (AFAR), University of Western Ontario, London, ON, Canada.
- Department of Biology, University of Saskatchewan, Saskatoon, SK, Canada.
| | - Keith A Hobson
- Department of Biology and Advanced Facility for Avian Research (AFAR), University of Western Ontario, London, ON, Canada
| | - Christopher G Guglielmo
- Department of Biology and Advanced Facility for Avian Research (AFAR), University of Western Ontario, London, ON, Canada
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Jonasson KA, Guglielmo CG. Evidence for spring stopover refuelling in migrating silver-haired bats (Lasionycteris noctivagans). CAN J ZOOL 2019. [DOI: 10.1139/cjz-2019-0036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Migrating animals must acquire sufficient fuel to sustain migratory movement, but how time is allocated to achieve this can vary greatly. The fuel strategies used by migrating bats are not well understood and have not been investigated during the spring when insectivorous bats face low food abundance. Migrating silver-haired bats (Lasionycteris noctivagans (Le Conte, 1831)) were captured at a stopover site in Long Point, Ontario, Canada, in April and May of 2012–2014. We followed the movements of 40 bats outfitted with radio transmitters using an automated telemetry array and examined the effects of ambient temperature, fat stores, and sex on stopover duration. As seen previously in autumn, most bats departed the evening following capture, but one-third of bats used multiday stopovers. Extended stopover was associated with lower ambient temperature. There was no effect of sex or fat at capture on stopover departure probability. Bats captured closer to dawn had greater fat mass and lean mass than those captured early in the night, a trend indicative of fuel deposition at this site. This is the first study to provide evidence that bats use stopover habitat for refuelling.
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Affiliation(s)
- Kristin A. Jonasson
- Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, 1393 Western Road, London, ON N6G 1G9, Canada
- Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, 1393 Western Road, London, ON N6G 1G9, Canada
| | - Christopher G. Guglielmo
- Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, 1393 Western Road, London, ON N6G 1G9, Canada
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Baloun DE, Guglielmo CG. Energetics of migratory bats during stopover: a test of the torpor-assisted migration hypothesis. J Exp Biol 2019; 222:jeb.196691. [DOI: 10.1242/jeb.196691] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 02/13/2019] [Indexed: 02/04/2023]
Abstract
The torpor-assisted migration hypothesis posits that migration is facilitated in bats by the use of torpor during stopover roosting periods, and predicts that at stopover bats regulate time in torpor facultatively so that daily energy expenditure is independent of ambient roosting temperature. Energy savings can thus be directed to migratory movement. However, direct measurements of total roosting energy expenditure in relation to ambient and body temperature are lacking. We captured migratory silver-haired bats (Lasionycteris noctivagans; ∼11g) at Long Point, Ontario, Canada in spring and fall 2016. We used quantitative magnetic resonance analysis to measure body composition change and energy expenditure over a twelve-hour roosting period in a ventilated incubator at 10, 17 and 25°C. We assessed the effects of season, body mass, sex and age on energy expenditure. We found that daily energy expenditure was independent of roosting temperature, and that this was achieved by flexible use of torpor. Variation in body mass at capture was driven mainly by differences in fat, and the amount of body fat was negatively related to torpor use, particularly in spring. Season, sex and age also affected torpor use and energy expenditure, notably with pregnant females being generally fatter and using less torpor than males in spring. We estimate that stopover contributes only 15-20% to the total energy costs of migration in bats compared to 70% or more in typical birds. This study provides support for the torpor-assisted migration hypothesis, and furthers our understanding of the energy budgets of migratory bats.
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Affiliation(s)
- Dylan E. Baloun
- Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada
| | - Christopher G. Guglielmo
- Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, London, Ontario, Canada
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Fraser EE, Brooks D, Longstaffe FJ. Stable isotope investigation of the migratory behavior of silver-haired bats (Lasionycteris noctivagans) in eastern North America. J Mammal 2017. [DOI: 10.1093/jmammal/gyx085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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Adams AM, Fenton MB. Identifying peaks in bat activity: a new application of SaTScan’s space–time scan statistic. WILDLIFE RESEARCH 2017. [DOI: 10.1071/wr16194] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Identifying key spatio–temporal periods of an organism’s activity is an important focus of many ecological studies. Bat activity, as assessed by passive acoustic monitoring, can be extremely variable and currently there exists no agreed-upon method for identifying periods of high activity.
Aims
We proposed a new application for the space–time scan statistic (SaTScan) as an objective technique for identifying peak periods of bat activity. We aimed to test the validity of SaTScan as a method for identifying peaks in bat activity and demonstrate its use for assessing species-specific temporal patterns of activity.
Methods
To evaluate the effectiveness of SaTScan for detecting peaks in activity, we compared SaTScan to peaks identified with percentile thresholds. We evaluated peaks in activity across three scales: within nights; among nights at a site; and among sites. We applied SaTScan to demonstrate analysis of species-specific activity as further use of this technique.
Key results
SaTScan was effective at identifying peak time periods that included the majority of the high activity minutes. Timing of peaks of activity was most consistent for Myotis lucifugus during swarming and Lasiurus borealis during migration. All other activity for five species at three sites was indicative of foraging activity, with peaks in the first 5h after sunset.
Conclusions
SaTScan can be a valuable tool for quickly identifying peaks in acoustic activity of bats, with an objective, replicable and statistically sound method that can be applied at many temporal and spatial scales.
Implications
This tool has the potential for many more applications in ecology. Beyond acoustic analyses of bat activity, this technique could easily identify peaks in a research or management context, such as study activity among habitats, commercial developments or years at a single site.
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Smith AD, McWilliams SR. Bat activity during autumn relates to atmospheric conditions: implications for coastal wind energy development. J Mammal 2016. [DOI: 10.1093/jmammal/gyw116] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Jonasson KA, Guglielmo CG. Sex differences in spring migration timing and body composition of silver-haired batsLasionycteris noctivagans. J Mammal 2016. [DOI: 10.1093/jmammal/gyw119] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Ciechanowski M, Jakusz-Gostomska A, Żmihorski M. Empty in summer, crowded during migration? Structure of assemblage, distribution pattern and habitat use by bats (Chiroptera: Vespertilionidae) in a narrow, marine peninsula. MAMMAL RES 2015. [DOI: 10.1007/s13364-015-0249-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Adams AM, McGuire LP, Hooton LA, Fenton MB. How high is high? Using percentile thresholds to identify peak bat activity. CAN J ZOOL 2015. [DOI: 10.1139/cjz-2014-0230] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Passive acoustic monitoring is a common tool used for monitoring bat activity levels. Identifying periods and locations of peak levels provides insight into bat ecology and has important management implications. One limitation of passive acoustic monitoring is the relative nature of the data, often relying on subjective interpretation of descriptive terminology such as “higher” or “lower”. We propose the use of percentile thresholds (PTs) for objectively identifying peak activity. By compiling a reference data set, it is possible to define percentiles of the observed activity levels and these percentiles can provide objective thresholds for comparing activity levels. We used acoustic recordings from sites in Canada and calculated PTs based on the distribution of the number of calls per hour across all nights and sites for three species of bat. Given species ecologies (e.g., hibernating, migrating), we were able to use PTs to objectively identify peak activity levels on a species-specific basis. Percentile thresholds are also a replicable method of describing within-night activity by evaluating species-specific activity patterns and important times of night. Our analyses and examples represent a proof of concept. The next step is to move towards a standardized distribution to generate PTs. Creating a public repository of acoustic data sets to evaluate activity of a species in the context of its entire range would allow us to standardize terms such as “high” activity in an objective manner.
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Affiliation(s)
- Amanda M. Adams
- Mitrani Department of Desert Ecology, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel
| | - Liam P. McGuire
- Department of Biological Sciences, Texas Tech University, Box 43131, Lubbock, TX 79409, USA
| | | | - M. Brock Fenton
- Department of Biology, The University of Western Ontario, London, ON N6A 5B7, Canada
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Sjollema AL, Gates JE, Hilderbrand RH, Sherwell J. Offshore Activity of Bats Along the Mid-Atlantic Coast. Northeast Nat (Steuben) 2014. [DOI: 10.1656/045.021.0201] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Seasonal survival probabilities suggest low migration mortality in migrating bats. PLoS One 2014; 9:e85628. [PMID: 24454906 PMCID: PMC3893227 DOI: 10.1371/journal.pone.0085628] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 12/06/2013] [Indexed: 11/25/2022] Open
Abstract
Migration is adaptive if survival benefits are larger than costs of residency. Many aspects of bat migration ecology such as migratory costs, stopover site use and fidelity are largely unknown. Since many migrating bats are endangered, such information is urgently needed to promote conservation. We selected the migrating Leisler's bat (Nyctalus leisleri) as model species and collected capture-recapture data in southern Switzerland year round during 6 years. We estimated seasonal survival and site fidelity with Cormack-Jolly-Seber models that accounted for the presence of transients fitted with Bayesian methods and assessed differences between sexes and seasons. Activity peaked in autumn and spring, whereas very few individuals were caught during summer. We hypothesize that the study site is a migratory stopover site used during fall and spring migration for most individuals, but there is also evidence for wintering. Additionally, we found strong clues for mating during fall. Summer survival that included two major migratory journeys was identical to winter survival in males and slightly higher in females, suggesting that the migratory journeys did not bear significant costs in terms of survival. Transience probability was in both seasons higher in males than in females. Our results suggest that, similarly to birds, Leisler's bat also use stopover sites during migration with high site fidelity. In contrast to most birds, the stopover site was also used for mating and migratory costs in terms of survival seemed to be low. Transients' analyses highlighted strong individual variation in site use which makes particularly challenging the study and modelling of their populations as well as their conservation.
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Krüger F, Clare EL, Symondson WOC, Keišs O, Pētersons G. Diet of the insectivorous bat Pipistrellus nathusii during autumn migration and summer residence. Mol Ecol 2013; 23:3672-83. [PMID: 24118366 DOI: 10.1111/mec.12547] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 09/10/2013] [Accepted: 09/13/2013] [Indexed: 11/29/2022]
Abstract
Migration is widespread among vertebrates, yet bat migration has received little attention and only in the recent decades has a better understanding of it been gained. Migration can cause significant changes in behaviour and physiology, due to increasing energy demands and aerodynamic constraints. Dietary shifts, for example, have been shown to occur in birds before onset of migration. For bats, it is not known if a change in diet occurs during migration, although breeding season-related dietary preference has been documented. It is known that a diet rich in fats and the accumulation of fat deposits do increase the flight range of migratory bats. Some bat species can be regarded as long-distance migrants, covering up to 2000 km between summer and winter roosting areas. Pipistrellus nathusii (Vespertilionidae), a European long-distant migrant, travels each year along the Baltic Sea from north-eastern Europe to hibernate in central and southern Europe. This study presents data on the dietary habits of migrating Pipistrellus nathusii compared with those during the breeding season. We analysed faecal samples from bats on fall migration caught at the Ornithological Field Station in Pape, Latvia and from samples collected in North-Latvian summer roosts. We applied both morphological identification and molecular methods, as morphological methods also recognize life stages of prey and can contribute frequency data. The diets of bats on migration and breeding bats were similar, with Diptera and Lepidoptera comprising the major prey categories. However, certain prey groups could be explained by the different hunting habitats exploited during migration vs. summer residence.
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Affiliation(s)
- Frauke Krüger
- Institute of Natural Resource Conservation, University of Kiel, Olshausenstr. 75, 24118, Kiel, Germany; Echolot Gbr, Eulerstr. 12, 48155, Münster, Germany
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Fraser EE, McGuire LP, Eger JL, Longstaffe FJ, Fenton MB. Evidence of latitudinal migration in tri-colored bats, Perimyotis subflavus. PLoS One 2012; 7:e31419. [PMID: 22384019 PMCID: PMC3284490 DOI: 10.1371/journal.pone.0031419] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 01/07/2012] [Indexed: 11/19/2022] Open
Abstract
Background Annual movements of tri-colored bats (Perimyotis subflavus) are poorly understood. While this species has been considered a regional migrant, some evidence suggests that it may undertake annual latitudinal migrations, similar to other long distance North American migratory bat species. Methodology/Principal Findings We investigated migration in P. subflavus by conducting stable hydrogen isotope analyses of 184 museum specimen fur samples and comparing these results (δDfur) to published interpolated δD values of collection site growing season precipitation (δDprecip). Results suggest that the male molt period occurred between June 23 and October 16 and 33% of males collected during the presumed non-molt period were south of their location of fur growth. For the same time period, 16% of females were south of their location of fur growth and in general, had not travelled as far as migratory males. There were strong correlations between δDfur from the presumed molt period and both growing season δDprecip (males – r2 = 0.86; p<0.01; females – r2 = 0.75; p<0.01), and latitude of collection (males – r2 = 0.85; p<0.01; females – r2 = 0.73; p<0.01). Most migrants were collected at the northern (>40°N; males and females) and southern (<35°N; males only) extents of the species' range. Conclusions/Significance These results indicate a different pattern of migration for this species than previously documented, suggesting that some P. subflavus engage in annual latitudinal migrations and that migratory tendency varies with latitude and between sexes. We suggest that this species' hibernation ecology makes it particularly susceptible to long winters, making migration from the northern extent of the species' range to more southern hibernacula preferable for some individuals. Fur δD values for some of the northern individuals may indicate an increase in the currently accepted northern range of this species. Sex-biased differences in migration may be the result of differences in reproductive pressures.
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Affiliation(s)
- Erin E Fraser
- Department of Biology, The University of Western Ontario, London, Ontario, Canada.
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Skalak SL, Sherwin RE, Brigham RM. Sampling period, size and duration influence measures of bat species richness from acoustic surveys. Methods Ecol Evol 2012. [DOI: 10.1111/j.2041-210x.2011.00177.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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McGuire LP, Guglielmo CG, Mackenzie SA, Taylor PD. Migratory stopover in the long-distance migrant silver-haired bat, Lasionycteris noctivagans. J Anim Ecol 2011; 81:377-85. [PMID: 21954938 DOI: 10.1111/j.1365-2656.2011.01912.x] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. Some bat species make long-distance latitudinal migrations between summer and winter grounds, but because of their elusive nature, few aspects of their biology are well understood. The need for migratory stopover sites to rest and refuel, such as used by birds, has been repeatedly suggested, but not previously tested empirically in bats. 2. We studied migrating silver-haired bats (Lasionycteris noctivagans) at Long Point, ON, Canada. We used digital radio-transmitters to track 30 bats using an array of five towers that effectively covered the entire region (c. 20 × 40 km). We measured stopover duration and departure direction, and documented movement patterns, foraging activity and roost sites. We measured body composition on arrival using quantitative magnetic resonance and simulated long-distance migration using observed body composition to predict migration range and rate. 3. Migration occurred in two waves (late August and mid-September). Most bats stayed 1-2 days, although two remained >2 weeks. One third of the bats foraged while at the site, many foraging opportunistically on nights when rain precluded continued migration. Bats roosted in a variety of tree species and manmade structures in natural and developed areas. Half of the bats departed across Lake Erie (minimum crossing distance c. 38 km) while half departed along the shoreline. 4. Simulations predicted a migration rate of c. 250-275 km per day and suggest that all but one of the bats in our study carried sufficient fuel stores to reach the putative wintering area (estimated distance 1500 km) without further refuelling. 5. Our results suggest that migrating bats stopover for sanctuary or short-term rest as opposed to extended rest and refuelling as in many songbirds. Daily torpor could reduce energy costs when not in flight, minimizing the need for extended stopovers and allowing bats to potentially complete their migration at a fraction of the time and energy cost of similar sized birds.
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Affiliation(s)
- Liam P McGuire
- Department of Biology, Advanced Facility for Avian Research, University of Western Ontario, 1151 Richmond St N, London, ON N6A 5B7, Canada.
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