The ontogeny and function of duet codes in territory dynamics of the riverside wren
Abstract
In some species of songbirds, both females and males sing and coordinate their
vocalizations to create highly complex joint performances known as duets. Additionally, in
some of these species, pair mates combine their individual vocalizations following consistent
pair-specific associations, known as duet codes. Investigating how birds create their
individual and pair repertoires and how duet codes are used in within- and between-pair
interactions is essential for understanding how each sex benefits from learning this complex
behaviour and to characterize the nature of the selective mechanisms that promoted the
evolution of this joint signaling system. This thesis focuses on a population of riverside
wrens, Cantorchilus semibadius, as a means to investigate the song learning strategies of
each sex, to elucidate the functions of duet codes in intra- and inter-sexual interactions, and
to measure the cooperative nature of the defence strategy of both sexes. To achieve these
goals I conducted a long-term study and a series of playback experiments. I found an
unusually high turnover rate compared to other duetting species. I also found that individual
and pair repertoires are considerably stable over time and are highly shared across the
population, which suggests that individuals create their repertoires as juveniles and settle
nearby their tutors, as vacancies arise frequently. During territory defence, partners
maintained a close distance with each other, both sexes approached closely to both
simulated intruders, and both sexes matched the songs of same-sex rivals at similar rates
but mostly sung in coordination with their partner. This indicates females and males benefit
from displaying a strong partnership and perform a joint defence against rivals. My thesis
suggests duetting is a cooperative behaviour and the function of duet codes might be mostly
related to within-pair interactions in the riverside wrens.
Type
Thesis, PhD Doctor of Philosophy
Rights
Embargo Date: 2021-05-28
Embargo Reason: Thesis restricted in accordance with University regulations. Print and electronic copy restricted until 28th May 2021
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