Sorry for the late posting, I was out of office for some time.
Frank Veit
Behaviour 142, Issue 8
http://www.ingentaconnect.com/content/brill/beh/2005/00000142/00000008
(Abstracts below)
Digweed, SM, LM Fedigan & D Rendall (2005) Variable specificity in the
anti-predator vocalizations and behaviour of the white-faced capuchin, Cebus
capucinus. Behaviour 142: 1003-1027.
Kunc, HP, V Amrhein & Naguib, Marc (2005) Acoustic features of song
categories and their possible implications for communication in the common
nightingale (Luscinia megarhynchos). Behaviour 142: 1083-1097.
Rios Chelen, AA, CM Garcia & K Riebel (2005) Variation in the song of a
sub-oscine, the vermilion flycatcher. Behaviour 142: 1121-1138.
_____________________
Abstracts:
Digweed, SM, LM Fedigan, D Rendall (2005) Variable specificity in the
anti-predator vocalizations and behaviour of the white-faced capuchin, Cebus
capucinus. Behaviour 142: 1003-1027.
Much research in animal communication is aimed at understanding the
functional design features of animal vocal signals. Our detailed analyses of
the vocalizations and behavioural responses elicited in white-faced
capuchins by predators and other disturbances point to two call variants
that differ modestly in their acoustic structure and that are accompanied by
functionally distinct behavioural responses. The first variant is given
exclusively to avian predators and is almost invariably accompanied by the
monkey's immediate descent from the treetops where it is most vulnerable;
therefore, we label this call variant the 'aerial predator alarm'. The
second variant, that differs only slightly but noticeably from the first, is
given to a wide range of snakes and mammals, including a range of species
that represent no predatory threat to the monkeys. This second call is also
associated with more variable responses from calling monkeys, from delayed
retreat from the source of disturbance, to active approach, inspection, and
sometimes mobbing of the animal involved. We therefore label this variant
more generally as an 'alerting call'. Although some other primate species
show a more diverse system of anti-predator calls, and the capuchins
themselves may yet be found to produce a greater variety of calls, a system
of two call variants with varying degrees of predator specificity and
behavioural response is not uncommon among primates and appears functionally
appropriate for capuchins. The basic structure of the alerting call allows
conspecific listeners to localize the caller and the source of disturbance
readily, thereby allowing listeners to approach and assist in mobbing in
cases where the disturbance warrants it, or to avoid the area in cases where
the disturbance is identified as a predatory threat. Conversely, the aerial
predator alarm is inherently less localizable and therefore conveys the
presence of a predator to conspecific listeners nearby while allowing the
signaler itself to remain relatively inconspicuous.
Kunc, HP, V Amrhein & Naguib, Marc (2005) Acoustic features of song
categories and their possible implications for communication in the common
nightingale (Luscinia megarhynchos). Behaviour 142: 1083-1097.
In many passerine species, males sing more than one distinct song type.
Commonly, songs are assigned to different song types or song categories
based on phonological and syntactical dissimilarities. However, temporal
aspects, such as song length and song rate, also need to be considered to
understand the possible functions of different songs. Common nightingales
(Luscinia megarhynchos) have large vocal repertoires of different song types
but their songs additionally can be grouped into two distinct categories
(particular groups of song types): whistle songs and nonwhistle songs.
Whistle songs are hypothesised to be important to attract migrating females.
We studied temporal properties of whistle songs and nonwhistle songs and
examined the relationship between those song parameters and song output
parameters, such as song rate and song length. To investigate how song
parameters vary among males, we calculated the coefficients of variation for
different song traits. We found that the variation in the proportion of
whistle songs was significantly higher among males than variation in other
song parameters. Furthermore, the proportion of whistle songs was negatively
correlated with other song output patterns. These findings suggest that the
production of whistle songs might be constrained and/or that whistle songs
and their succeeding pauses may act as a functional unit in communication.
Rios Chelen, AA, CM Garcia & K Riebel (2005) Variation in the song of a
sub-oscine, the vermilion flycatcher. Behaviour 142: 1121-1138.
Most studies on song variation have focused on oscine birds, whereas
sub-oscine singing has seldom been described in detail, with variation in
song structure and performance rarely quantified. Yet this information is
required to formulate hypotheses regarding possible coding of individuality,
motivational or breeding status, and also for a more informed comparison of
oscine versus sub-oscine song. To this end we recorded songs of 12
territorial males of a Central Mexican population of the vermilion
flycatchers (Pyrocephalus rubinus) throughout the breeding season. We found
that: (1) although all males sang only one general form of song, both song
structure and performance showed substantial seasonal and inter-individual
variation; (2) this variation was most pronounced in the number of
introductory elements; (3) after the onset of nest construction, both the
number of introductory elements and the song rate changed. We discuss some
possible functions of this variation.
|