<tt>Here are the bioacoustics articles from J Mammalogy 85(2). 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>
<br>
<tt><br>Broders, Hugh G., C. Scott Findlay, and Ligang Zheng. 2004. Effects of
clutter on echolocation call structure of Myotis septentrionalis and M.
lucifugus. Journal of Mammalogy, 85(2):273-281.</tt><br>
<br>
<tt>ABSTRACT: The structure of echolocation calls, and the distance over which
bats perceive their environment, varies with the amount of structural
clutter through which they are flying. Clutter and species had significant
effects on the frequency-time characteristics of search-phase echolocation
calls of northern long-eared (Myotis septentrionalis) and little brown bats
(M. lucifugus). We tested an a priori derived model that predicted the
pattern of differences in echolocation call variable values among clutter
categories would provide insight into the relative maximum distances that
bat species could perceive using echolocation. Specifically, the model
predicted that species adapted to flying and foraging in cluttered habitats
would have a shorter maximum perceptual distance than species adapted to
flying and foraging in uncluttered habitats. The results supported this
model and suggest the clutter-adapted M. septentrionalis had a shorter
maximum perceptual distance than M. lucifugus, a species known to forage in
a variety of habitats but mainly in uncluttered areas (i.e., over water).
Using calls as the sampling unit, a neural network correctly
classified >94% of the echolocation calls to species in high clutter. In
medium and low clutter, >82% of the calls were correctly classified to
species; however >90% correct classification was achieved by leaving <30%
of calls unclassified. Researchers should develop clutter-specific call
libraries to improve species classification accuracy for echolocation
calls.</tt><br>
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<tt><br>Mandelli, Marie-Juliette, and Gillian Sales. 2004. Ultrasonic
vocalizations
of infant short-tailed field voles, Microtus agrestis. Journal of
Mammalogy, 85(2):282-289.</tt><br>
<br>
<tt>ABSTRACT: Ultrasonic vocalizations of infant rodents are used in
developmental studies and for investigating the effects of drugs or
environmental pollutants. Few studies, however, have analyzed the frequency
characteristics of these ultrasonic vocalizations. This study investigates
the physical and vocal development of infants (1?14 days old) of the
short-tailed field vole, Microtus agrestis, under 2 conditions of
isolation: at 23 degrees C immediately after being isolated from the nest
or at 23 degrees C after 10 min of isolation at 27 degrees C. Seventy-three
percent of the infants vocalized, and there was great variation among
calling infants in the number of vocalizations emitted. More infants,
especially males, called during the 2nd period of isolation than during the
1st, and latency to call increased with age in males. The ultrasonic
vocalizations were comparable to those recorded from North American voles.
Vocalizations were classified into 7 categories on the basis of
characteristics of the fundamental frequency. Simple calls were emitted
most commonly and became more frequent in older infants, whereas the
proportion of calls with a down-sweep in frequency and audible clicks
decreased with age. The emission of ultrasonic calls, therefore, appears to
reflect changes both in physical development of the infants and in their
external environment.</tt><br>
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<tt><br>Schleich, Cristian Eric, and Cristina Busch. Functional morphology of
the
middle ear of Ctenomys talarum (Rodentia: Octodontidae). Journal of
Mammalogy, 85(2):290-295.</tt><br>
<br>
<tt>ABSTRACT: The middle ear of the solitary subterranean rodent Ctenomys
talarum was studied. The most significant features observed were the
enlarged middle-ear cavity, a round and larger eardrum without pars
flaccida, no connection between malleus and the tympanic bone, partial
fusion of malleus with incus, a nearly flat stapedial footplate, absence of
stapedial artery, reduced tensor tympani, and absence of stapedial muscle.
Some of these features are shared with unrelated subterranean rodents like
Spalax ehrenbergi and geomyids, possibly as adaptations for low-frequency
hearing.</tt><br>
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<tt><br>There was also a book review of Kunz and Fenton, 2003, Bat Ecology
(Journal
of Mammalogy, 85(2):366-367). I've downloaded a PDF of this as well for
interested list members.</tt><br>
<br>
<tt>--------------------------------------------------------------------------------------------<br>
Brian R. Mitchell<br>
Post-Doctoral Associate<br>
University of Vermont<br>
The Rubenstein School of Environment and Natural Resources<br>
George D. Aiken Center<br>
81 Carrigan Drive<br>
Burlington, VT 05405-0088<br>
(802) 656-2496<br>
[EMAIL PROTECTED]<br>
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</tt><br>
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