Bioacoustic papers in Behaviour 147 vol. 8 (July 2010)
http://www.ingentaconnect.com/content/brill/beh/2010/00000147/00000008
(Abstracts below)
Benedict, L (2010) California towhee vocal duets are multi-functional
signals for multiple receivers. Behaviour 147: 953-978.
Pangle, WM & KE Holekamp (2010) Age-related variation in threat-sensitive
behavior exhibited by spotted hyenas: observational and experimental
approaches. Behaviour 147: 1009-1033.
Kondo, N, EI Izawa & S Watanabe (2010) Perceptual mechanism for vocal
individual recognition in jungle crows (Corvus macrorhynchos): contact call
signature and discrimination. Behaviour 147: 1051-1072.
Abstracts:
Benedict, L (2010) California towhee vocal duets are multi-functional
signals for multiple receivers. Behaviour 147: 953-978.
Avian vocal duets provide a model system for studying the evolution and
production of complex signals which require input from multiple individuals.
Duets serve a variety of communication functions in diverse species. To
explore the function of duetting in California towhees (Pipilo crissalis) I
collected behavioural data from a marked population, conducted sound
playback experiments, and removed males from established pairs to observe
the behaviour of new partners. Results indicate that California towhees use
duets during extra-pair communication with conspecifics and during
intra-pair communication between duetting partners. During the breeding
season duetting frequency peaked during the chick-rearing period and was low
during periods of high female fertility. Playbacks provoked similar levels
of aggressive response from male and female territory holders. Mated pairs
duetted in response to simulated intrusion by conspecific males, females and
pairs. California towhee duets briefly increased in frequency after pairing,
and showed no evidence of change due to learning. Duets facilitate spatial
and behavioural coordination by mates, which should allow them to more
effectively perform behaviours related to mutual reproductive success. No
single existing hypothesis adequately explains vocal duetting among
California towhees. Instead, duets function in multiple contexts and provide
multiple potential benefits.
Pangle, WM & KE Holekamp (2010) Age-related variation in threat-sensitive
behavior exhibited by spotted hyenas: observational and experimental
approaches. Behaviour 147: 1009-1033.
We examined ontogenetic variation in threat-sensitive behaviors exhibited by
spotted hyenas (Crocuta crocuta). We documented naturally-occurring
vigilance throughout ontogeny, and used playback experiments to evaluate
age-related variation in hyenas' responses to control sounds or lion roars.
We inquired whether juveniles respond to lions more cautiously than do
adults. Naturalistic observations showed that juveniles are less vigilant
than adults when no immediate threat is present, but more vigilant than
adults when lions are present. Our playback experiments revealed that both
adult and juvenile hyenas moved in response to lion roars but not to control
sounds, and their reactions were stronger to roars emitted by male than
female lions. However, juveniles showed a stronger response to lions than
adults, as expressed by spending more time avoiding speakers after roar
onset, and by having a shorter latency to first movement than adults. Like
adults, juvenile hyenas, thus, appear to recognize certain signals as
dangerous and respond accordingly. However, our data suggest that young
hyenas may need experience with danger early in life to learn the
environmental circumstances under which they ought to be vigilant when no
threat is immediately apparent.
Kondo, N, EI Izawa & S Watanabe (2010) Perceptual mechanism for vocal
individual recognition in jungle crows (Corvus macrorhynchos): contact call
signature and discrimination. Behaviour 147: 1051-1072.
In long-range fission-fusion complex societies, individuals are often
recognized by audiovocal signals because of long-range propagation. The
signature voice system is a well-known mechanism involving both acoustic
individuality of a certain call type and discrimination ability. Previous
studies on vocal individual recognition of birds have emphasized its
involvement in breeding contexts such as mate, parent and offspring, and
territorial-neighbour recognition. However, there has been less focus on the
recognition of non-breeding flock members despite the socio-ecological
demand of such ability in the complex social lives of highly social birds
including corvids. Here we report a signature voice system in jungle crows
by showing both acoustic individuality of contact calls and discrimination
ability. We first performed a discriminant functional analysis on contact ka
calls of five crows to examine their discriminatory potential and
demonstrate inter-individual distinctions. We next used an operant
conditioning to verify the perceptual ability to discriminate non-breeding
familiar conspecifics based on ka calls. Four of the five crows successfully
transferred discrimination of individual calls to the novel ka calls. Our
results provide the first evidence of a signature voice system as a
perceptual mechanism for individual recognition of familiar individuals in
non-breeding flocks of a highly social crow.
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