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Effects of physical and social environment on zebra finches’ foraging intensity

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posted on 2023-08-25, 02:02 authored by Anika Immer

The zebra finch (Taeniopygia guttata) is the most widely used passerine bird in captive research, yet little work has been done in the wild where physical and social conditions are more variable and their behaviour can be investigated in an ecological context. Zebra finches forage on the ground and are vulnerable to predation by a range of terrestrial and aerial predators. In this thesis, I explore how the physical and social environment affects their foraging decisions in captivity and in the wild. The decision to feed in a particular patch is an attempt to optimise the costs and benefits of feeding at that location. I used giving-up densities (GUD) – the density of food remaining in a patch after the forager(s) have exploited it, to measure the perceived risk of zebra finches to a variety of experimental treatments. In captivity, I investigated how zebra finches’ foraging intensity responded to characteristics of the captive environment such as the availability of perches, cover, and ground substrate. In the wild, I examined how their foraging intensity was affected by the distance to natural cover (vegetation) or their visual fields. I also explored effects of the local neighbourhood density of zebra finches in the wild. I further investigated captive zebra finches’ foraging intensity in different sized groups, as a function of the proximity to, and behaviour of neighbouring flocks. I show that zebra finches forage more intensively when they are close to vegetation and perceive cover as protective. I also found that foraging intensity increased non-linearly with group size and mass and sex mitigated how social and physical environments affected foraging intensity. Overall, my finding suggest that while foraging, zebra finches place greater emphasis on their social, compared to physical environments. My thesis highlights the importance of taking into account a wide range of social factors when investigating foraging decisions by animals.

History

Table of Contents

Chapter I. General Introduction -- Chapter II. Giving up density as a tool to study welfare in captive birds -- Chapter III. Giving up densities in wild zebra finches: spatial and temporal effects on foraging intensity -- Chapter IV. The effect of sight lines on the foraging behaviour of zebra finches in the wild -- Chapter V. Zebra finches’ actions rather than presence or numbers affects neighbours’ food patches exploitation intensity -- Chapter VI. Foraging with conspecifics: group size, group mass and the similarity of group members’ masses affect giving up densities in Zebra finches -- Chapter VII. Pairing status influences how thoroughly zebra finches exploit food patches -- Chapter VIII. General Discussion

Notes

Cotutelle thesis in conjunction with the University of Exeter

Awarding Institution

Macquarie University ; University of Exeter

Degree Type

Thesis PhD

Department, Centre or School

Department of Biological Sciences

Year of Award

2019

Principal Supervisor

Simon Griffith

Additional Supervisor 1

Sasha Dall

Rights

Copyright: The Author Copyright disclaimer: https://www.mq.edu.au/copyright-disclaimer

Language

English

Extent

140 pages

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