(Abstracts see below)
Behaviour vol. 145 no. 2 & 3 (February & March 2008)
http://www.ingentaconnect.com/content/brill/beh/2008/00000145/00000002
http://www.ingentaconnect.com/content/brill/beh/2008/00000145/00000003
Sanvito, S, F Galimberti & EH Miller (2008) Development of aggressive
vocalizations in male southern elephant seals (Mirounga leonina): maturation
or learning? Behaviour 145: 137-170.
Neudorf, DLH, BJM Stutchbury & WH Piper (2008) The function of breeding
season chip calls by female hooded warblers (Wilsonia citrina). Behaviour
145: 231-250.
Leighty, KA, J Soltis, K Leong & A Savage (2008) Antiphonal exchanges in
African elephants (Loxodonta africana): collective response to a shared
stimulus, social facilitation, or true communicative event? Behaviour 145:
297-312.
Anderson, RC, WA Searcy & S Nowicki (2008) Testing the function of
song-matching in birds: responses of eastern male song sparrows Melospiza
melodia to partial song-matching. Behaviour 145: 347-363.
- Abstracts -
Sanvito, S, F Galimberti & EH Miller (2008) Development of aggressive
vocalizations in male southern elephant seals (Mirounga leonina): maturation
or learning? Behaviour 145: 137-170.
Vocalizations are an important component of male elephant seal agonistic
behaviour. Acoustic and behavioural components of vocalizations emitted
during agonistic contests show gross differences between young and old
males, but the variation with age depends on the specific feature.
Vocalizations become more frequent and effective at later ages. Acoustic
features that are constrained by structural phenotype, which changes with
age, also should change with age, while acoustic features that are
independent from structural phenotype should show no relationship with age.
We demonstrate that, in southern elephant seals, formant frequencies, which
are constrained by the vocal tract length and, therefore, by body size, show
a clear decrease with age, whereas temporal and structural features of
sounds, which potentially are unconstrained, show no correlation with age.
Formants ontogeny seems, therefore, to be mostly the result of body
maturation, and hence formants may be reliable signals of age. In contrast,
acoustic features such as temporal features and syllable structure, are free
to change, and hence may serve as the raw material for vocal learning and
individual recognition.
Neudorf, DLH, BJM Stutchbury & WH Piper (2008) The function of breeding
season chip calls by female hooded warblers (Wilsonia citrina). Behaviour
145: 231-250.
We document use of 'chip' vocalizations by breeding female hooded warblers
(Wilsonia citrina) and propose explanations for the function of the calls.
Fertile females (building or laying stage) chip differently than incubating
females, via a lower chip rate, shorter bouts of chipping and more bouts per
hour. Females responded to playbacks of fertile chipping and a female model
on their territories by approaching and chip calling. Resident males were
generally not responsive to their mate's chip calls and did not move closer
when their mates chipped; however, neighbouring males often intruded onto
territories in response to female chip calls. Neighbouring males did not
distinguish between playbacks of fertile and incubation chip calls, but
responded to both at equally low frequencies. Radio-tracked neighbouring
males intruded onto territories significantly more frequently when females
were chipping than when they were silent. Such intrusions likely function as
extra-pair mating attempts. Finally, variation in call pattern among fertile
females did not correlate with frequency of extra-pair young. Our study
provides some support that chip calls of hooded warblers function in female
territory defence and attraction of potential extra-pair males but further
testing of these hypotheses is required.
Leighty, KA, J Soltis, K Leong & A Savage (2008) Antiphonal exchanges in
African elephants (Loxodonta africana): collective response to a shared
stimulus, social facilitation, or true communicative event? Behaviour 145:
297-312.
Female African elephants are thought to exchange 'rumble' vocalizations, but
such temporally associated calls may not constitute communicative events.
Affiliated females are more likely to engage in antiphonal calling, but
affiliation is defined according to time spent in proximity. Affiliated
partners may vocalize in sequence simply because their proximity causes them
to collectively respond to shared external stimuli or due to a social
facilitation effect. We used bi-variate and partial correlation analyses to
test for the independent effects of the strength of the social relationship
and distance between vocal partners on the likelihood of a vocal response.
Female African elephants at Disney's Animal Kingdom were video-taped and
outfitted with audio-recording collars that allowed for the individual
identification of low-frequency rumbles. Affiliation had a strong influence
on response likelihood, even after controlling for the effects of the
distance between vocalizing partners. Further, the distance between
vocalizing partners did not correlate with response likelihood, and
factoring out the effects of affiliation did not significantly alter this
result. These results suggest that rumble exchanges are communicative events
that reflect social bonds, not simply artifacts of increased proximity and,
therefore, provide support for functional hypotheses concerning rumble
exchanges in wild African elephants.
Anderson, RC, WA Searcy & S Nowicki (2008) Testing the function of
song-matching in birds: responses of eastern male song sparrows Melospiza
melodia to partial song-matching. Behaviour 145: 347-363.
Song-matching has been hypothesized to be a signal of aggressive intentions
whereby matching an opponent signals that the singer is likely to attack.
Theory predicts that an aggressive signal should impose a cost that enforces
the signal's reliability. A receiver-dependent cost imposed by the matched
bird's aggressive retaliation has been proposed for song-matching. We tested
for such a cost for partial song-matching in an eastern population of song
sparrows where males lack the shared song types necessary for song type
matching, but can perform partial song-matching using shared song segments.
We tested aggressive response, as measured by average distance to a playback
speaker, to partial-matching songs and non-matching songs. We predicted a
stronger aggressive response to partial-matching songs, as has been shown
for whole song-matching in western song sparrow populations. The birds in
our study responded no differently to partial-matching and non-matching
songs. Neither the distance to the playback speaker nor singing responses
differed between playback treatments. Our results do not support a
receiver-dependent cost to partial song-matching, as would be expected if
partial-matching is a direct threat. Instead, we suggest that partial
song-matching functions as a signal of attention.
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