Members of this list can download the following articles from
http://www.uvm.edu/~bmitchel/Bioacoustics.html.
Feighny, J. A., K. E. Williamson, and J. A. Clarke. 2006. North American
elk bugle vocalizations: male and female bugle call structure and
context. Journal of Mammalogy 87(6):1072-1077.
Bugle calls of male North American elk (Cervus elaphus) are common
sounds during fall in the Canadian and United States Rocky Mountains. In
contrast, bugle calls of female elk are rarely heard. We quantified the
acoustic structure of elk bugle calls, which is an essential 1st step to
understanding of the function of the call. We also investigated whether
motivation–structural rules apply to these long-distance calls. We
measured male elk bugle calls in Rocky Mountain National Park, Colorado,
during autumn of 1998 and 1999 and we measured female elk bugle calls on
2 Colorado elk ranches (private establishments that raise elk for
commercial purposes) during spring of 2001 and 2002. All bugle calls had
3 segments: on-glide, whistle, and off-glide. Male bugle calls were
longer in duration than female bugle calls (P , 0.01). Bugle calls
emitted in aggressive interactions had 4 or 5 low-frequency formants,
resulting in harsher, wider bandwidth bugles (P , 0.001) compared to the
tonal calls emitted in nonaggressive contexts, which lacked formants.
Thus, elk bugle calls appear to conform to motivational-structural rules.
O'Shea, Thomas, and Lynn B. Poche, Jr. 2006. Aspects of underwater sound
communication in Florida manatees (Trichechus manatus latirostris).
Journal of Mammalogy 87(6):1061-1071.
We recorded underwater vocalizations of captive and wild Florida
manatees (Trichechus manatus latirostris) to assess variability in
acoustic structure of their sounds and to test hypotheses regarding the
importance of specific acoustic traits in individual distinctiveness and
in certain behavioral contexts. Manatees use vocalizations to maintain
contact when in groups. The highest rates of vocalizing occur during
antiphonal calling between females and calves. Vocalizations are
complex, single-note calls with multiple harmonics, frequency
modulations, nonharmonically related overtones, and other nonlinear
elements. We measured 6 acoustic variables and found that individuals
varied significantly in fundamental frequency, emphasized band,
frequency range, and call contour (the overall pattern of complexity in
frequency modulation). These traits did not vary within individuals on
different dates or when manatees were alarmed and fleeing. Individual
fundamental frequencies ranged from 1.75 to 3.90 kHz, and were
negatively correlated with body size. Little sound energy occurred above
18 kHz in 502 call notes of 6 captive manatees sampled with a recording
oscilloscope. Presence of harmonics and call duration differed by date
and manatees emitted longer calls when fleeing disturbance. Call
duration varied from 118 to 643 ms (geometric mean ¼ 271 ms, 95%
confidence limits ¼ 264, 279 ms) in a sample of 479 vocalizations we
recorded from 14 individuals. The maximum call duration recorded over
the entire study was 900 ms. Females and calves responded only to each
others’ vocalizations when rejoining a group after brief separations,
strongly suggesting individual recognition by sound. Structural
complexity in the calls of manatees is similar to that in other
sirenians, and may reflect their auditory capabilities and the unique
physical properties of sound in shallow water.
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