The Structure, Development and Role of Song in Dippers
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The structure, development and role of song in dippers. Lucy Magoolagan Thesis submitted for the degree of Doctor of Philosophy April 2017 This thesis is my own work, and has not been submitted in substantially the same form for the award of a higher degree elsewhere. Word count: 41,886 Contents Acknowledgements Chapter 1: General introduction ....................................................................................................1 1.1 Introduction ..........................................................................................................................1 1.1.1 Male song .....................................................................................................................2 1.1.2 Female song ..................................................................................................................3 1.2 Song development ................................................................................................................4 1.3 The developmental stress hypothesis ..................................................................................6 1.3.1 Brood size ....................................................................................................................7 1.3.2 Parental care .................................................................................................................7 1.3.3 Weather .........................................................................................................................8 1.3.4 Parasite load ..................................................................................................................8 1.3.5 Pollution .......................................................................................................................9 1.3.6 Adaptations to stress ....................................................................................................9 1.4 Aims and thesis outline .....................................................................................................11 1.5 The dipper, Cinclus cinclus ...............................................................................................13 1.5.1 Introduction ................................................................................................................13 1.5.2 Adaptations to aquatic life ..........................................................................................14 1.5.3 Habitat and territory quality ........................................................................................14 1.5.4 Breeding ecology ........................................................................................................15 1.5.5 Diet and foraging behavior ........................................................................................16 1.5.6 An indicator of environmental quality ........................................................................17 1.5.7 Song ...........................................................................................................................19 Chapter 2: General methods .........................................................................................................20 2.1 Study site and population ...................................................................................................20 2.1.1 Study site ....................................................................................................................20 2.1.2 Age, sex and body size ...............................................................................................20 2.1.3 Breeding ecology .......................................................................................................22 2.1.4 Provisioning rate ........................................................................................................23 2.2 Song analyses ....................................................................................................................24 2.2.1 Song recording and analyses ......................................................................................24 2.2.2 Acoustic structure ......................................................................................................24 2.3 Territory quality ................................................................................................................27 2.3.1 Kick sampling ............................................................................................................27 2.3.2 Water chemistry .........................................................................................................27 Chapter 3: Structure and function of male and female song .......................................................29 3.1 Abstract .............................................................................................................................29 3.2 Introduction .......................................................................................................................30 3.3 Methods .............................................................................................................................33 3.3.1 Song recording and spectrogram production .............................................................33 3.3.2 Acoustic structure ......................................................................................................34 3.3.3 Behavioural context ...................................................................................................34 3.3.4 Seasonal trends ...........................................................................................................35 3.3.5 Statistical analyses .....................................................................................................35 3.4 Results ...............................................................................................................................36 3.4.1 Acoustic structure and sex .........................................................................................36 3.4.1.1 Complexity characteristics ......................................................................................36 3.4.1.2 Frequency characteristics ........................................................................................36 3.4.1.3 Temporal characteristics .........................................................................................39 3.4.2 Acoustic structure and behavioural context ...............................................................39 3.4.2.1 Complexity characteristics ......................................................................................39 3.4.2.2 Frequency characteristics ........................................................................................39 3.4.2.3 Temporal characteristics .........................................................................................39 3.4.2 Female song context and seasonal trends ...................................................................42 3.5 Discussion .........................................................................................................................45 3.6 Conclusion ........................................................................................................................48 Chapter 4: Playback experiment investigating female song function and territoriality in pairs.. 49 4.1 Abstract .............................................................................................................................49 4.2 Introduction .......................................................................................................................50 4.3 Methods .............................................................................................................................53 4.3.1 Study site and species ................................................................................................53 4.3.2 Song recordings .........................................................................................................53 4.3.3 Playback file construction ..........................................................................................53 4.3.4 Playback design ..........................................................................................................54 4.3.5 Statistical analyses .....................................................................................................57 4.4 Results ...............................................................................................................................58 4.4.1 Responses by breeding stage ......................................................................................58 4.4.2 Pre- versus post-incubation responses .......................................................................58 4.4.3 Pair responses .............................................................................................................58 4.4.4 Latency to respond .....................................................................................................59 4.5 Discussion .........................................................................................................................59 4.6 Conclusion ........................................................................................................................66 Chapter 5: The effect of early life conditions on song characteristics in males ..........................67 5.1 Abstract .............................................................................................................................67