Wattle function and territoriality in the South Island saddleback (Philesturnus carunculatus)1

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Biological Sciences
Degree name
Bachelor of Science (Hons)
Publisher
University of Canterbury. Biological Sciences
Journal Title
Journal ISSN
Volume Title
Language
Date
2014
Authors
Lloyd-Jones, David
Abstract

The South Island saddleback (Philesturnus carunculatus) is an endangered bird endemic to New Zealand. Both males and females possess wattles, which are colourful fleshy structures that hang from the lower beak. Although a wide range of birds have wattles, the selection pressures and behavioural function of these biological ornaments remain poorly understood. In this study, behavioural observations, morphological measures, and a playback experiment were used to investigate how wattles are used by South Island saddlebacks in their natural habitat. Wattles were found to be monomorphic when body mass was accounted for, and they were observed to engorge in both aggressive and non-aggressive visual displays. In the playback experiment, wattle engorgement in saddlebacks was significantly associated with territorial intrusions in males but not in females, although females were significantly more likely to engorge their wattles and display in the absence of their mate. Larger males with bigger wattles did not have significantly stronger territorial responses. These results provide the first experimental evidence for the functional role that wattle engorgement plays in saddleback signalling behaviour. The markedly similar visual display behaviour between sexes, which is used in both aggressive and non-aggressive contexts, provides insight into possible selection pressures acting in the evolutionary maintenance of wattles.

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Citation
Keywords
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Field of Research::06 - Biological Sciences::0603 - Evolutionary Biology
Fields of Research::31 - Biological sciences::3109 - Zoology::310901 - Animal behaviour
Rights
Copyright David Lloyd-Jones
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