A COMPARATIVE ANALYSIS OF EVOLUTIONARY CHANGES IN ISLAND BIRDS A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Science in Ecology in the University of Canterbury By TOMMY FLUEN University of Canterbury 2008 ii Table of Contents LIST OF FIGURES..................................................................................................................................... V LIST OF TABLES......................................................................................................................................VI LIST OF APPENDICES............................................................................................................................VI ABSTRACT................................................................................................................................................... 1 CHAPTER 1 .................................................................................................................................................. 3 1.1 GENERAL INTRODUCTION Background ........................................................................................................................................... 3 Outline of thesis .................................................................................................................................... 6 1.2 REFERENCES .......................................................................................................................................11 CHAPTER 2 ................................................................................................................................................16 A COMPARATIVE STUDY OF THE NESTLING VOCALISATIONS OF NEW ZEALAND AND INTRODUCED EUROPEAN PASSERINES 2.1 ABSTRACT ..........................................................................................................................................16 2.2 INTRODUCTION ...................................................................................................................................17 2.3 METHODS............................................................................................................................................21 Study site and species used.................................................................................................................21 Recording Procedure..........................................................................................................................22 Analysis of Recordings .......................................................................................................................23 Statistical Analysis..............................................................................................................................24 2.4 RESULTS .............................................................................................................................................24 2.5 DISCUSSION ........................................................................................................................................25 2.6 REFERENCES .......................................................................................................................................31 iii CHAPTER 3 ................................................................................................................................................39 OLFACTORY CRYPSIS: DO NEW ZEALAND PASSERINES MODIFY THEIR UROPYGIAL SECRETIONS DURING THE BREEDING SEASON? 3.1 ABSTRACT ..........................................................................................................................................39 3.2 INTRODUCTION ...................................................................................................................................40 3.3 MATERIALS AND METHODS...............................................................................................................44 Collection of preen waxes. .................................................................................................................44 Sample extraction and Gas Chromatography analysis....................................................................45 Interpretation of chromatograms.......................................................................................................46 Statistical analysis. .............................................................................................................................47 3.4 RESULTS. ............................................................................................................................................48 3.5 DISCUSSION. .......................................................................................................................................49 3.6 REFERENCES.......................................................................................................................................54 CHAPTER 4 ................................................................................................................................................63 AN INVESTIGATION OF EVOLUTIONARY CHANGES IN COLOURATION, SIZE AND MORPHOLOGY OF INSULAR PASSERINES 4.1 ABSTRACT. .........................................................................................................................................63 4.2 INTRODUCTION...................................................................................................................................64 4.3 METHODS............................................................................................................................................67 Size.......................................................................................................................................................70 Colour..................................................................................................................................................71 Statistical analysis. .............................................................................................................................73 4.4 RESULTS. ............................................................................................................................................73 Changes in body size ..........................................................................................................................73 Changes in colouration ......................................................................................................................74 4.5 DISCUSSION. .......................................................................................................................................75 4.6 REFERENCES.......................................................................................................................................83 CHAPTER 5 ................................................................................................................................................94 5.1 GENERAL DISCUSSION iv 5.2 REFERENCES.....................................................................................................................................100 ACKNOWLEDGMENTS .......................................................................................................................102 APPENDIX 1.............................................................................................................................................103 v List of Figures Figure 2.1. Figure detailing the extraction of the following 34 characteristics from a sonogram: max power, call length, frequency range and high and low frequency Figure 2.2 Box-plots comparing the frequency ranges of nestling 35 begging calls in native New Zealand birds (n = 6) and introduced European birds (n = 6). Figure 2.3. Boxplots comparing the maximum frequencies, the 36 frequency at which most energy is attributed, of nestling begging calls in native New Zealand birds (n = 6) and introduced European birds (n = 6). Figure 2.4. Examples of sonograms produced from the begging 37-38 vocalisations of introduced and native nestling birds. Figure 3.1. Sampling the preen waxes from the uropygial gland of a 59 dunnock in the field, Kaikoura Figure 3.2. Typical chromatogram of a breeding (continental) 60 greenfinch Carduelis chloris. Figure 3.3 Typical chromatogram for a breeding (island) bellbird 61 Anthornis melanura. Figure 4.1. Graph showing the percentage of species pairs in which the 89 island species showed an increase in the specified trait. (Body ‘size’ was estimated using mass, length, and author’s notes to come to approximation of which species was larger. Mass used weight data only). The line at 50% represents the percentage of pairs expected to show an increase by chance; the null hypothesis. (* = p ≤ 0.1, ** = p ≤ 0.05, *** = p < 0.000). Figure 4.2. Scatter plot of the Log transformed initial mass of 90 continental species vs their proportional change in mass in the island form. Figure 4.3. Example of a reduction in carotenoid pigmentation of an 91 island species compared to its continental counterpart. Figure 4.4. Example of an increase in melanin pigmentation in an island 92 species compared to its continental counterpart. Note also the reduction in the buff wash (carotenoid pigments) in the island species as well. vi Figure 4.5. Example of increased melanism in island species compared 93 to their continental counterpart, resulting in reduction of contrasting patterns and loss