<tt>Here are the bioacoustics articles from J Mammalogy 85(1). I've downloaded
PDFs of all articles in this e-mail, and will save them for a few weeks. If
list members need copies feel free to e-mail me a request.</tt><br>
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<tt>Ibáñez, Carlos, Javier Juste, Ricardo López-Wilchis, and Arturo
Núñez-Garduño. 2004. Habitat variation and jamming avoidance in
echolocation calls of the Sac-Winged Bat (Balantiopteryx plicata). Journal
of Mammalogy 85(1):38-42.<br>
ABSTRACT: We have studied the effect of habitat and presence of
conspecifics on echolocation characteristics of the emballonurid bat
Balantiopteryx plicata. Calls during the search phase only showed
differences between habitats in bandwidth, as has been found for other
open-space bats. Characteristics of calls during the approach phase did
change when bats entered open areas. Calls in the terminal phase showed no
differences in the characters examined between habitats. Bats flying in
groups shifted their peak frequency significantly, which maximized
differences between individuals. These results are interpreted as an active
mechanism of jamming avoidance. Bats flying in groups also tended to
increase the mean of peak frequencies.</tt><br>
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<tt>Eiler, Karen Christine, and Sandra Anne Banack. 2004. Variability in the
alarm call of Golden-Mantled Ground Squirrels (Spermophilus lateralis and
S. saturatus). Journal of Mammalogy 85(1):43-50.<br>
ABSTRACT: Many animals have geographic variation or dialect differences in
their vocalizations. These differences combined with social behavior and
isolation can contribute to speciation. We compared the acoustic
vocalizations of 3 subspecies of Spermophilus lateralis and those of S.
saturatus using wild-caught animals in the presence of a predator, Canis
lupus familiarus. Variation was examined using 9 sonogram variables. We
found both local dialect differences and geographic variation in alarm
calls. S. saturatus could be distinguished 100% of the time from S.
lateralis using discriminant analysis. Widespread use of ultrasonic
vocalizations was found in both S. lateralis and S. saturatus. Dialect
differences showed a pattern of character displacement between adjacent
subspecies. Vocalization parameters changed within local sites and between
years, suggesting alarm calling is at least partially a learned behavior.
Species share more uniquely defining vocalization variables than either
subspecies or local populations.</tt><br>
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<tt>Keeley, Annika T. H., and Brian W. Keeley. 2004. The mating system of
Tadarida brasilensis (chiroptera: molossidae) in a large highway bridge
colony. Journal of Mammalogy 85(1):113-119.<br>
ABSTRACT: We observed mating by Brazilian free-tailed bats (Tadarida
brasiliensis) in central Texas between 21 March and 5 April 1998. We
documented copulations in large and small day roosts and in temporary night
roosts. Focal animal sampling at a highway bridge revealed an aggressive
and a passive male copulation strategy that may function as adaptations to
different roost conditions. During aggressive copulation, the male
separates a female from a roost cluster and restricts her movements during
mating while he emits characteristic calls. During passive copulation, the
male moves very slowly onto a female that roosts in a dense cluster.
Passive copulations occur without resistance from the female and without
male vocalizations. Both males and females mate with multiple partners,
suggesting that mating is promiscuous. The mating system in a large highway
bridge colony is characterized as mating aggregations or swarming because
mating occurs in large, temporally unstable multimale and multifemale
mating groups, with no apparent male territories or defense of
females.</tt><br>
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<tt><br>--------------------------------------------------------------------------------------------<br>
Brian R. Mitchell<br>
Ph.D. Candidate<br>
University of California, Berkeley<br>
Department of Environmental Science, Policy and Management<br>
[EMAIL PROTECTED]<br>
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