University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 3-16-2017 Consistency of Structural Color across Molts: The Effects of Environmental Conditions and Stress on Feather Ultraviolet Reflectance Rebecca Lynn Windsor University of South Florida, [email protected] Follow this and additional works at: http://scholarcommons.usf.edu/etd Part of the Biology Commons Scholar Commons Citation Windsor, Rebecca Lynn, "Consistency of Structural Color across Molts: The Effects of Environmental Conditions and Stress on Feather Ultraviolet Reflectance" (2017). Graduate Theses and Dissertations. http://scholarcommons.usf.edu/etd/6782 This Thesis is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Consistency of Structural Color across Molts: The Effects of Environmental Conditions and Stress on Feather Ultraviolet Reflectance by Rebecca L. Windsor A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science with a concentration in Ecology and Evolution Department of Integrative Biology College of Arts and Sciences University of South Florida Co-Major Professor: Reed Bowman, Ph.D. Co-Major Professor: Gordon Fox, Ph.D. Stephen Deban, Ph.D. Date of Approval: March 20, 2017 Keywords: Aphelocoma coerulescens, scrub-jay, UV color, plumage consistency, corticosterone Copyright © 2017, Rebecca L. Windsor DEDICATION This work is dedicated to the jays, who captured my heart from the start, and who will hopefully continue to capture hearts for decades to come. ACKNOWLEDGEMENTS This work would not have been possible without the constant support of my advisors, Reed and Gordon, who tirelessly answered all of my questions and gave me input. I thank Archbold Biological Station and the Cornell Lab of Ornithology for continued lodging and research support. Project guidance and emotional support were provided by Shane Pruett and Angela Tringali, who helped convince me that I really was a competent member of the field. Corticosterone administration guidance was provided by Stephen Schoech, Thomas Small, Emily Elderbrock, and Blake Jones. I also want to thank Lynn Siefferman, who provided endless guidance and troubleshooting advice on the spectrometer. Lastly, thank you to the countless interns and collaborators who helped collect data for the demography project at Archbold Biological Station. TABLE OF CONTENTS LIST OF TABLES ....................................................................................................................................... iii LIST OF FIGURES ...................................................................................................................................... v ABSTRACT ................................................................................................................................................. vi INTRODUCTION ........................................................................................................................................ 1 Literature Review............................................................................................................................. 1 Ornamentation .................................................................................................................... 1 Consistency of Structural Plumage Color ........................................................................... 2 Florida Scrub-Jays .............................................................................................................. 3 Effects of Environmental Conditions on Plumage Variation .............................................. 5 Nutritional condition. ............................................................................................. 5 Social environment. ............................................................................................... 7 Parasites. ................................................................................................................ 8 Habitat quality........................................................................................................ 9 Stress. ................................................................................................................... 10 Reproductive Fitness ......................................................................................................... 11 Questions and Hypotheses ............................................................................................................. 12 METHODS ................................................................................................................................................. 15 Study Site and Juvenile Feather Collection ................................................................................... 15 Corticosterone Administration ....................................................................................................... 16 Blood and Adult Feather Collection .............................................................................................. 17 Environmental Parameters ............................................................................................................. 17 Nutritional Condition ........................................................................................................ 18 Social Environment ........................................................................................................... 18 Parasites ............................................................................................................................ 18 Habitat Quality .................................................................................................................. 18 Stress ................................................................................................................................. 19 Breeding Observations ................................................................................................................... 19 Spectroscopy .................................................................................................................................. 19 Statistical Analysis ......................................................................................................................... 20 RESULTS ................................................................................................................................................... 22 Tri-stimulus Color Measures ......................................................................................................... 22 Consistency of Color...................................................................................................................... 22 Effects of Environmental Conditions ............................................................................................. 23 Juvenile Plumage Color .................................................................................................... 23 Adult Plumage Color ........................................................................................................ 25 Relative Change in Plumage Color ................................................................................... 27 Effects of corticosterone. ..................................................................................... 28 i Effects of Color on Reproduction .................................................................................................. 29 DISCUSSION ............................................................................................................................................. 31 Consistency of Color...................................................................................................................... 31 Effects of Environmental Conditions ............................................................................................. 34 Juvenile vs. Adult Color ................................................................................................... 34 Relative Change in Reflectance ........................................................................................ 36 Effects of Corticosterone .................................................................................................. 37 Effects of Color on Reproduction .................................................................................................. 38 Conclusions .................................................................................................................................... 40 REFERENCES ........................................................................................................................................... 42 TABLES ..................................................................................................................................................... 49 FIGURES .................................................................................................................................................... 62 APPENDICES ............................................................................................................................................ 75 Appendix A: Effects of Individual Variables on Florida Scrub-Jay Rectrix Color ....................... 76 ii LIST OF TABLES Table