Anthropogenic noise alters bat activity levels and echolocation calls

We investigated the effects of insect-attracting ultraviolet lights on activity of forest bats (Microchiroptera) with the prediction that lights would increase our indices of bat activity and improve species identification of recorded echolocation calls. Insect aggregations were created on forest tracks (n = 9) near Kioloa, New South Wales, using three vertically stratified insect light traps. Bat echolocation calls were recorded using a ground-based vertically oriented Anabat II detection system. Bat activity and foraging rates were higher at lit points than at unlit points, particularly when the lights were operated in full darkness. More species were identified at lit points and the sampling time required to identify the second to the fifth new species was 3.3–4.6 times shorter with lights. The presence of lights resulted in a greater number of bat passes more than five pulses in length, which was associated with an increased ability to identify passes to species level. Our study demonstrates that the use of lights in forest-based echolocation surveys can improve bat species inventories, particularly in communities where overlap in call characteristics among species is common.

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Going, going, gone: the impact of white-nose syndrome on the summer activity of the little brown bat ( Myotis lucifugus )

Biology Letters ◽

10.1098/rsbl.2010.0859 ◽

2010 ◽

Vol 7 (3) ◽

pp. 392-394 ◽

Cited By ~ 56

Author(s):

Yvonne Dzal ◽

Liam P. McGuire ◽

Nina Veselka ◽

M. Brock Fenton

Keyword(s):

Hudson River ◽

Myotis Lucifugus ◽

Activity Levels ◽

Echolocation Calls ◽

Bat Activity ◽

White Nose Syndrome ◽

Little Brown Bat ◽

The Impact ◽

Little Brown Bats

Since its discovery in the winter of 2005–2006, white-nose syndrome (WNS) has killed over one million little brown bats ( Myotis lucifugus ) in the American northeast. Although many studies have reported die-offs of bats at winter hibernacula, it is important to understand how bat mortality linked to WNS at winter hibernacula affects bat activity levels in their summer ranges. In the summer (May–August) of 2007, 2008 and 2009, we recorded echolocation calls to determine bat activity at sites along the Hudson River, NY (within approx. 100 km of where WNS was first reported). We documented a 78 per cent decline in the summer activity of M. lucifugus , coinciding with the arrival and spread of WNS. We suggest that mortality of M. lucifugus in winter hibernacula is reflected by reduced levels of activity in the summer and that WNS affects the entire bat population of an area, and not only individual hibernacula.

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Canopy and edge activity of bats in a quaking aspen (Populus tremuloides) forest

Canadian Journal of Zoology ◽

10.1139/z2012-049 ◽

2012 ◽

Vol 90 (7) ◽

pp. 798-807 ◽

Cited By ~ 3

Author(s):

T.W. Pettit ◽

K.T. Wilkins

Keyword(s):

Populus Tremuloides ◽

High Frequency ◽

Regression Tree ◽

Low Frequency ◽

Tree Height ◽

Quaking Aspen ◽

Activity Levels ◽

Forest Canopies ◽

Bat Activity ◽

Cart Analysis

Characteristics of edges affect the behavior of species that are active in and near edges. Forest canopies may provide edge-like habitat for bats, though bat response to edge orientation has not been well examined. We sampled bat activity in quaking aspen ( Populus tremuloides Michx.) forest canopies and edges in Heber Valley, Utah, during summer 2009 using Anabat detectors. Categorization and regression tree (CART) analysis of echolocation characteristics (e.g., frequency, duration) identified two guilds based on characteristic frequency (i.e., high- and low-frequency guilds). We used linear regression to compare characteristics of canopy and edge vegetation (e.g., tree height, diameter at breast height) to bat activity levels. Activity levels of high-frequency bats did not respond differentially to edge vegetation; low-frequency bat activity seemed to respond to canopy height. Activity levels of high-frequency bats were significantly greater than low-frequency bats in both edges and canopies. We detected significantly more bat activity in forest edges than in forest canopies, indicating the importance of edges to bats in forests.

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Bat activity over calm and turbulent water

Canadian Journal of Zoology ◽

10.1139/z87-035 ◽

1987 ◽

Vol 65 (2) ◽

pp. 219-222 ◽

Cited By ~ 30

Author(s):

Beatrix von Frenckell ◽

Robert M. R. Barclay

Keyword(s):

Water Level ◽

Frequency Analysis ◽

Myotis Lucifugus ◽

Prey Abundance ◽

Sticky Traps ◽

Insect Abundance ◽

Echolocation Calls ◽

Bat Activity ◽

Little Brown Bat ◽

Turbulent Water

A comparison of the activity of the little brown bat (Myotis lucifugus) over calm pools and fast-flowing riffles was performed in southwestern Alberta. Bat activity was assessed by monitoring echolocation calls using ultrasonic detectors. Activity was higher over pools than riffles. This could be due to differences in prey abundance or accessibility in the two habitats. Alternatively, water noise at turbulent sites may interfere with the bats' echolocation abilities. Sticky traps were used to assess prey abundance, and water noise was recorded for intensity–frequency analysis. Insect abundance at the height where the bats flew (< 1 m above the water) did not differ between sites, but insects close to or at water level at calm pools may be more accessible than at fast-flowing riffles. Further, water noise at riffles may decrease the efficiency with which bats detect targets.

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Seasonal Activity Patterns of Two Species of Nyctophilus Bats Based on Mist-Net Captures.

Australian Mammalogy ◽

10.1071/am98349 ◽

1998 ◽

Vol 20 (3) ◽

pp. 349

Author(s):

R.M. Brigham ◽

F. Geiser

Keyword(s):

Activity Patterns ◽

Activity Cycle ◽

Activity Levels ◽

Seasonal Activity ◽

Daily Torpor ◽

Bat Activity ◽

Annual Activity ◽

A Site ◽

Mist Net

We evaluated the annual activity cycle of Nytophilus gouldi and N. geoffroyi using 82 nights of mist-netting data from a site near Armidale in northern NSW. Our purpose was to assess whether these bats hibernated or used short bouts of daily torpor combined with foraging on at least some nights. During the cold months of the year (May - August) bat activity levels inferred from net captures was very low providing support for the hypothesis that these bats use daily torpor and at least sometimes actively forage as opposed to entering hibernation.

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Concentration of bat activity in riparian habitats over an elevational gradient

Canadian Journal of Zoology ◽

10.1139/z99-062 ◽

1999 ◽

Vol 77 (6) ◽

pp. 972-977 ◽

Cited By ~ 77

Author(s):

S D Grindal ◽

J L Morissette ◽

R M Brigham

Keyword(s):

Elevational Gradient ◽

Relative Activity ◽

Activity Levels ◽

Riparian Areas ◽

Habitat Types ◽

Bat Activity ◽

Prey Resources ◽

Riparian Habitats ◽

Mist Net ◽

Capture Rates

Riparian areas are generally assumed to represent important foraging areas for insectivorous bats, but this contention has rarely been formally quantified. To test this assumption, we used bat detectors to compare the relative activity levels of a community of temperate-zone bat species between riparian (lake) and upland (cutblock) habitats at three different elevations (ranging from 540 to 1800 m) in a forested area of southern British Columbia. In addition, we also investigated the sex and age class distributions of bats (based on mist-net captures) between riparian and upland habitats among the elevational zones. Bat activity levels were significantly greater in riparian than upland areas (10 and 40 times greater for foraging and commuting activity, respectively). Capture rates were greater in riparian areas and biased towards females, suggesting that female bats may preferentially select riparian areas, probably because of the abundant prey resources typically associated with this habitat. Captures of females also predominated at lower elevations, whereas males were captured more often in higher elevation zones. Our data support the assumption that riparian habitats represent important foraging and probably drinking areas for bats. The sex bias and differences in capture rates and activity levels need to be considered when designing bat surveys in different habitat types or over elevational gradients.

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Bats of Kootenay, Glacier, and Mount Revelstoke national parks in Canada: identification by echolocation calls, distribution, and biology

Canadian Journal of Zoology ◽

10.1139/z83-332 ◽

1983 ◽

Vol 61 (11) ◽

pp. 2503-2508 ◽

Cited By ~ 35

Author(s):

M. B. Fenton ◽

H. G. Merriam ◽

G. L. Holroyd

Keyword(s):

British Columbia ◽

National Parks ◽

National Park ◽

Myotis Lucifugus ◽

Glacier National Park ◽

Lasiurus Cinereus ◽

Echolocation Calls ◽

Bat Activity ◽

Lasionycteris Noctivagans ◽

The Town

We studied the behaviour, echolocation calls, and distribution of bats in Kootenay, Glacier, and Mount Revelstoke national parks in British Columbia, Canada. Presented here are keys for identification of nine species of bats by their echolocation calls as rendered by two different bat-detecting systems. The species involved include Myotis lucifugus, M. evotis, M. volans, M. septentrionalis, M. californicus, Lasionycteris noctivagans, Eptesicus fuscus, Lasiurus cinereus, and L. borealis. The distribution of these species within the three parks was assessed by capturing bats in traps and mist nets and by monitoring of their echolocation calls. Most of the species exploited concentrations of insects around spotlights, providing convenient foci of activity for assessing distribution. Although most species of Myotis were commonly encountered away from the lights, Lasiurus cinereus in Kootenay National Park was only regularly encountered feeding on insects at lights. This species was not detected in Glacier National Park, and although we regularly encountered it in the town of Revelstoke, it was rarely encountered in Mount Revelstoke National Park. Another focus of bat activity was small pools in cedar forest in Mount Revelstoke National Park. This involved high levels of Myotis spp. activity at dusk as the bats came to the pools to drink.

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Eavesdropping by bats on the feeding buzzes of conspecifics

Canadian Journal of Zoology ◽

10.1139/z07-060 ◽

2007 ◽

Vol 85 (7) ◽

pp. 795-801 ◽

Cited By ~ 69

Author(s):

E.H. Gillam

Keyword(s):

Echolocation Call ◽

Tadarida Brasiliensis ◽

Echolocation Calls ◽

Insect Prey ◽

Bat Activity

Echolocation calls of most bats are emitted at high intensities and subject to eavesdropping by nearby conspecifics. Bats may be especially attentive to “feeding buzz” calls, which are emitted immediately before attack on airborne insects and indicate the potential presence of prey in the nearby area. Although previous work has shown that some species are attracted to feeding buzzes, these studies did not provide a well-controlled test of eavesdropping, as comparisons were made between responses to natural and altered signals (e.g., forward versus backward broadcasts of calls). In this study, I assessed the importance of feeding buzzes by conducting playbacks of controlled echolocation stimuli. I presented free-flying Brazilian free-tailed bats, Tadarida brasiliensis (I. Geoffroy, 1824), with echolocation call sequences in which feeding buzz calls were either present or absent, as well as a silence control. I determined levels of bat activity by counting the number of echolocation calls and bat passes recorded in the presence of each stimulus, and found significantly greater bat activity in response to broadcasts that contained feeding buzzes than to broadcasts without feeding buzzes or to the silence control. These results indicate that bats are especially attentive to conspecific feeding buzz calls and that eavesdropping may allow a bat to more readily locate rich patches of insect prey.

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An investigation of urban bat ecology in Baltimore, Maryland

10.32469/10355/69936 ◽

2019 ◽

Author(s):

◽

Ela Sita Carpenter

Keyword(s):

Species Richness ◽

Census Data ◽

Urban Landscape ◽

Acoustic Monitoring ◽

Activity Levels ◽

Baltimore County ◽

Vacant Lots ◽

Bat Activity ◽

Socioeconomic Variables ◽

Neighborhood Scale

In North America, bats are a taxon of concern that play an important role in insect control, and their response to urbanization varies. I wanted to discover if evaluating environmental and socioeconomic variables present in an urban landscape can help determine what bat species were present and how active these species were. Research occurred in Baltimore, Maryland, a 'shrinking' city in the eastern US, which had no prior research on the bat community. For my first project, I used active acoustic monitoring to evaluate how bat activity levels (amount of detected acoustic sequences) and the bat community varied along both a direct and indirect rural to urban gradient. Nine sites along the Gwynns Falls watershed in Baltimore County and City were used the gradient. Over 1,500 sequences (detection files) were recorded from six species and I found that the direct and indirect measures of urbanization gradient used are not a predictor of bat presence and activity. For my next project I used passive acoustic monitoring to record bat activity at 32 vacant lots within Baltimore City to determine which environmental and socioeconomic variables best predict bat species richness and activity at these small, informal, understudied urban greenspaces. Environmental and socioeconomic data was obtained using on-site measures, GIS, and US Census data. There were no predictors for overall species richness. Canopy-associated measures at both the site and neighborhood scale, streetlights, site distance from water and the urban core, residential race and income, old housing, and rental housing were all common predictors of bat species' activity levels. Species relationships with these predictors varied and some species had additional predictors, suggesting that bats use the urban landscape to different degrees. Some larger lots could potentially be managed to have vegetation structural complexity (allowing both canopy cover and open space to accommodate bat species with different traits), but many lots are too small to do this. Vacant lots closer to water and larger patches of forests have the most potential to be managed for bats.

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Winter activity of boreal bats

Mammalian Biology ◽

10.1007/s42991-021-00111-8 ◽

2021 ◽

Author(s):

Anna S. Blomberg ◽

Ville Vasko ◽

Melissa B. Meierhofer ◽

Joseph S. Johnson ◽

Tapio Eeva ◽

...

Keyword(s):

Site Selection ◽

Barometric Pressure ◽

Acoustic Monitoring ◽

Passive Acoustic Monitoring ◽

Rock Outcrops ◽

Echolocation Calls ◽

Bat Activity ◽

Winter Activity ◽

Passive Acoustic ◽

Positive Effect

AbstractNatural hibernation sites used by bats in areas that lack cave features have long remained unresolved. To investigate hibernation site selection and winter activity of boreal bats, we recorded bat calls using passive acoustic monitoring at 16 sites in South-Western Finland. These sites included four rock outcrops with crevices and cave features, three glacial erratics or boulder fields, three ancient shores, three root cellars and three control sites where we did not expect bats to be overwintering. Our results revealed echolocation calls of Eptesicus nilssonii, Plecotus auritus and Myotis sp. We recorded significantly more activity near rock outcrops compared to other habitats, excluding root cellars. We also found that ambient temperature had a positive effect on bat activity and found evidence that P. auritus may be using low barometric pressure as a proxy for suitable foraging conditions during the winter. Our results suggest that rock outcrops may be more important to bats than previously acknowledged, highlighting the need to take these sites in account in planning of conservation measures. Furthermore, our findings underline the suitability of using acoustic monitoring in homing on hibernation sites that are not otherwise accessible.

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