The echolocation calls of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats as adaptations for long- versus short-range foraging strategies and the consequences for prey selection

1986 ◽  
Vol 64 (12) ◽  
pp. 2700-2705 ◽  
Author(s):  
Robert M. R. Barclay
Keyword(s):  
Prey Selection ◽  
Foraging Strategy ◽  
Prey Detection ◽  
Constant Frequency ◽  
Insectivorous Bats ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Close Range ◽  
Search Approach ◽  
Lasionycteris Noctivagans

Amongst aerial-feeding insectivorous bats, differences in the design of echolocation calls appear to be associated with differences in foraging strategy. Recordings and observations of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats in Manitoba, Canada, support such an association. Lasionycteris noctivagans use multiharmonic search–approach calls with an initial frequency sweep and a constant frequency tail. Such calls are suited for bats foraging in the open but near obstacles, and pursuing prey detected at relatively close range. This is the foraging strategy employed by this relatively slow, manoeuverable species. Lasiurus cinereus employ single harmonic search–approach calls that are low (20–17 kHz), essentially constant frequency signals. Calls of this design are suited for long-range target detection in open air situations, the foraging strategy used by L. cinereus. Differences in call design may explain dietary differences between the two species. Lasiurus cinereus consistently prey on large insects. The low, constant frequency design of their calls means that small insects are detectable only at close range and are thus difficult for this fast-dying bat to catch. The broad-band calls used by L. noctivagans do not restrict prey detection and these bats prey on a wider range of insects. Similar restrictions on prey detection, caused by echolocation call specializations, may be important in producing what might otherwise be considered active prey selection by some insectivorous bats.

Long- versus short-range foraging strategies of hoary (Lasiurus cinereus) and silver-haired (Lasionycteris noctivagans) bats and the consequences for prey selection

1985 ◽  
Vol 63 (11) ◽  
pp. 2507-2515 ◽  
Author(s):  
Robert M. R. Barclay
Keyword(s):  
Short Range ◽  
Prey Availability ◽  
Prey Selection ◽  
Foraging Strategy ◽  
Foraging Strategies ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Straight Line ◽  
Lasionycteris Noctivagans ◽  
Selection Of

Habitat use, temporal activity, foraging behaviour, and prey selection of hoary bats (Lasiurus cinereus) and silver-haired bats (Lasionycteris noctivagans) were studied at Delta Marsh, Manitoba. Bat activity was assessed by monitoring echolocation calls with ultrasonic detectors. Prey availability was determined using sticky and Malaise traps and dietary information was obtained from fecal analysis. Both species were active all night and foraged primarily in the lee of a narrow forested ridge. Lasionycteris noctivagans foraged in a manner that indicates that it detects and pursues prey over short distances. These bats fly slowly, are highly manoeuverable, and were commonly observed feeding on swarms of insects in small clearings. They use echolocation calls that support the notion of a short-range foraging strategy and feed opportunistically on whatever insects are available. Lasiurus cinereus, on the other hand, uses a long-range prey detection and pursuit foraging strategy. They fly rapidly along straight line paths in open areas and use echolocation calls designed to detect insects at a distance. The diet consists primarily of large insects (moths, beetles, and dragonflies), but the bats nonetheless feed opportunistically. The foraging strategy likely restricts the availability and profitability of small insects as prey.

Echolocation and feeding behaviour of Taphozous mauritianus (Chiroptera: Emballonuridae)

1980 ◽  
Vol 58 (10) ◽  
pp. 1774-1777 ◽  
Author(s):  
M. B. Fenton ◽  
G. P. Bell ◽  
D. W. Thomas
Keyword(s):  
Long Range ◽  
Feeding Behaviour ◽  
Second Harmonic ◽  
Feeding Strategy ◽  
Rapid Rise ◽  
Constant Frequency ◽  
Insectivorous Bats ◽  
Sound Energy ◽  
Echolocation Calls ◽  
Human Ear

Observations of free-flying bats in the field in Zimbabwe indicated that Taphozous mauritianus uses multiharmonic constant frequency (CF) search calls followed by multiharmonic approach and terminal calls that combine shallow and steep frequency modulated (FM) sweeps during approaches to targets. The three phases of calls all have rapid rise times to full amplitude, and most of the sound energy is in the second harmonic; the fundamental is usually present (11–13 kHz), making the calls clearly audible to the unaided human ear. This combination of characters, but particularly the CF search calls, serves to distinguish these echolocation calls from those of other insectivorous bats. One light-tagged individual hunting insects reacted to targets at distances of about 3 m, suggesting a long-range feeding strategy.

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

1983 ◽  
Vol 61 (11) ◽  
pp. 2503-2508 ◽  
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.

The influence of structural clutter on activity patterns of insectivorous bats

1997 ◽  
Vol 75 (1) ◽  
pp. 131-136 ◽  
Author(s):  
R. M. Brigham ◽  
S. D. Grindal ◽  
M. C. Firman ◽  
J. L. Morissette
Keyword(s):  
Prey Availability ◽  
Activity Patterns ◽  
Three Dimensional ◽  
Habitat Type ◽  
Habitat Choice ◽  
Insectivorous Bats ◽  
Lasiurus Cinereus ◽  
Direct Contrast ◽  
And Control ◽  
Lasionycteris Noctivagans

We experimentally tested the hypothesis that three-dimensional structural clutter is a major factor affecting habitat choice by insectivorous bats. To do this we artificially increased clutter at two sites used by bats without affecting prey availability. Our measure of available insect prey did not differ between treatment and control sites, indicating that only the spatial complexity of the habitat type was manipulated. Artificial clutter negatively affected foraging activity by small bats (Myotis spp.), supporting the hypothesis that physical clutter does affect foraging by bats. In direct contrast to our expectation, large bats (Eptesicus fuscus, Lasiurus cinereus, Lasionycteris noctivagans) were apparently unaffected by the clutter treatment. We suggest that this may be an artifact of our experimental design, because our ultrasonic detectors probably recorded large bats flying above the artificial clutter.

The diet of the insectivorous Hawaiian hoary bat (Lasiurus cinereus semotus) in an open and a cluttered habitat

1999 ◽  
Vol 77 (10) ◽  
pp. 1603-1608 ◽  
Author(s):  
David S Jacobs
Keyword(s):  
Foraging Strategy ◽  
Foraging Efficiency ◽  
Insect Fauna ◽  
Detection Range ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Insect Prey ◽  
Open Habitat ◽  
Hoary Bat ◽  
Lasiurus Cinereus Semotus

The Hawaiian hoary bat, Lasiurus cinereus semotus, foraged in both an open and a cluttered habitat. In the cluttered habitat it used slow, manoeuvring flight. In the open habitat it used rapid, less manoeuvring flight with echolocation calls of higher frequency than in the cluttered habitat. The combination of faster flight with higher frequency echolocation calls means that it should detect insect prey too late to manoeuvre for capture unless it preyed on relatively larger insects in the open habitat. The mean size of dietary items should therefore be greater in the open habitat than in the cluttered habitat. There should also be a greater preponderance of larger insects in the open than in the cluttered habitat to ensure that the use of rapid flight with higher frequency echolocation calls is efficient. I tested these predictions by comparing the diets and insect fauna in one open site with those in one closed site on the island of Hawai'i. As predicted, the dietary items were larger (t = 60.9, df = 259, p < 0.00001) in the open habitat (length = 18.9 ± 1.3 mm (mean ± SD); range 14-24 mm) than in the cluttered habitat (6.5 ± 1.6 mm; range 4-15 mm). In the cluttered habitat 86% of the insects fell into the three smallest length categories, while 52% of the insects in the open habitat fell into the two largest length categories. The preponderance of larger insects in the open habitat, with the consequent increase in detection range, enabled the bats to increase their flight speed despite their use of higher frequency echolocation calls. Rapid flight increases the rate at which insect prey are encountered and improves the foraging efficiency of bats. This provides evidence that bats are capable of altering their foraging strategy in response to prey characteristics and not just to the physical environment.

Habitat use by foraging insectivorous bats

1987 ◽  
Vol 65 (2) ◽  
pp. 284-288 ◽  
Author(s):  
C. L. Furlonger ◽  
H. J. Dewar ◽  
M. B. Fenton
Keyword(s):  
Habitat Use ◽  
Rural Areas ◽  
Urban Areas ◽  
Foraging Activity ◽  
Insectivorous Bats ◽  
Widespread Species ◽  
Lasiurus Borealis ◽  
Lasiurus Cinereus ◽  
Echolocation Calls ◽  
Study Sites

We monitored echolocation calls to measure the activity of insectivorous bats at study sites in southwestern Ontario during the summer of 1985, relying on feeding buzzes to identify foraging activity. Eptesicus fuscus was the most common and widespread species in the area, while Lasiurus cinereus and Lasiurus borealis were widespread. Species in the genus Myotis were more restricted in their distribution, being more common in an area with potential hibernacula. None of the species foraged exclusively in one habitat and all species exploited concentrations of insects around lights. Only E. fuscus made significant use of lights as foraging sites in urban areas while in town and rural areas all of the species foraged around lights.

Echolocation and feeding behaviour in four species of Myotis (Chiroptera)

1979 ◽  
Vol 57 (6) ◽  
pp. 1271-1277 ◽  
Author(s):  
M. Brock Fenton ◽  
Gary P. Bell
Keyword(s):  
Frequency Component ◽  
Maximum Energy ◽  
Myotis Lucifugus ◽  
Frequency Range ◽  
Constant Frequency ◽  
Similar Frequency ◽  
Echolocation Calls ◽  
Close Range ◽  
Feeding Area ◽  
Pass Through

We have compared the echolocation and feeding behaviours of Myotis lucifugus, M. californicus, M. volans, and M. auriculus based on observations and recordings of bats in the field. Myotis lucifugus and M. californicus appeared to detect prey at close range (≤ 1 m) and regularly made several attempts to capture insects over short distances; both used similar frequency-modulated echolocation calls. Myotis volans detected prey at greater distances (5–10 m), made only one attempt to capture insects per pass through a feeding area, and used an echolocation call with a distinct constant-frequency component. Myotis auriculus fed mainly on resting insects, mostly moths. The echolocation calls of this species were of shorter duration, lower intensity, broader frequency range with a higher frequency of maximum energy, and showed an initial upward sweep in frequency relative to the calls of the other Myotis we studied. Myotis auriculus did not increase their pulse repetition rate as they closed with stationary prey, and they appeared to fix on resting insects from about 2 m. This species rarely made more than one attempt to capture an insect per pass through a feeding area.

Activity Patterns, Habitat Use, and Prey Selection by Some African Insectivorous Bats

Biotropica ◽  
1977 ◽  
Vol 9 (2) ◽  
pp. 73 ◽  
Author(s):  
M. B. Fenton ◽  
N. G. H. Boyle ◽  
T. M. Harrison ◽  
D. J. Oxley
Keyword(s):  
Habitat Use ◽  
Prey Selection ◽  
Activity Patterns ◽  
Insectivorous Bats

Activity patterns and habitat preferences of insectivorous bats in a West African forest–savanna mosaic

2004 ◽  
Vol 20 (4) ◽  
pp. 397-407 ◽  
Author(s):  
Christoph F. J. Meyer ◽  
Christian J. Schwarz ◽  
Jakob Fahr
Keyword(s):  
Open Space ◽  
Activity Patterns ◽  
Habitat Preferences ◽  
Light Trap ◽  
Negative Influence ◽  
Foraging Activity ◽  
The Moon ◽  
Constant Frequency ◽  
Insectivorous Bats ◽  
Bat Activity

We studied activity patterns and habitat use by insectivorous bats in Comoé National Park, Ivory Coast. Bat foraging activity was quantified along five transects representing three different habitat types using acoustic monitoring and captures with mist nets and harp traps. Aerial insect abundance was assessed using a light trap; in addition shrub and tree arthropods were sampled. Bat activity was significantly and positively related to insect availability and ambient temperature, whereas increased visibility of the moon had a negative influence on flight activity. Together, these factors best explained both total bat activity and activity of bats hunting in open space and edge habitats. The interaction between temperature and light intensity was the best predictor of activity by species foraging in obstacle-rich forest habitats, however, the regression model had a low predictive value. Overall, a large proportion (c. 50%) of the variation in bat activity appeared to be a consequence of transect- and/or habitat-specific influences. We found a significant non-linear relationship between the activity of QCF (quasi-constant frequency) and FM–QCF (frequency modulated – quasi-constant frequency) bats and the phase of the moon, with lowest levels of activity occurring near full moon. We interpret this lunar-phobic behaviour as a reflection of a higher predation risk during moonlit periods. For FM (steep frequency modulated) and CF (constant frequency) bats, no significant correlation was found, although there was a trend suggesting that these bats at least were not negatively affected by bright moonlight. Foraging activity of bats was positively correlated with the abundance of atympanate moths; however, no such correlation was found for tympanate moths.

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