MIGRATION PATTERNS OF FLAMMULATED OWLS (PSILOSCOPS FLAMMEOLUS) USING LIGHT-LEVEL GEOLOCATORS ____________ A Thesis Presented to the Faculty of California State University, Chico ____________ In Partial Fulfillment of the Requirements for the Degree Master of Science in Biological Sciences ____________ by © Shannon Rich Fall 2018 MIGRATION PATTERNS OF FLAMMULATED OWLS (PSILOSCOPS FLAMMEOLUS) USING LIGHT-LEVEL GEOLOCATORS A Thesis by Shannon Rich Fall 2018 APPROVED BY THE INTERIM DEAN OF GRADUATE STUDIES: ________________________________ Sharon Barrios, Ph.D. APPROVED BY THE GRADUATE ADVISORY COMMITTEE: ________________________________ ________________________________ Christopher T. Ivey, Ph.D. Colleen A. Hatfield, Ph.D., Chair Graduate Coordinator ________________________________ ________________________________ Donald G. Miller, Ph.D. Raymond J. Bogiatto II, M.S. PUBLICATION RIGHTS No portion of this thesis may be reprinted or reproduced in any manner unacceptable to the usual copyright restrictions without the written permission of the author. iii ACKNOWLEDGEMENTS This project was a huge collaborative effort across four states that spanned multiple years and many dedicated field crews in order to learn more about this wonderful and elusive species. This project would not have been possible without the funding by the U.S. Fish and Wildlife Service and the mentorship of David H. Johnson, who worked as a technical advisor to teach me everything he knew about geolocators and catching owls. I am forever grateful for the knowledge given to us by Brian Linkhart, whose work with flammulated owls has spanned over 3 decades, and the use of his Colorado field site. I am grateful to the guidance of Markus Mika and his field crew in the use of his Utah study sites. David Oleyar came out to Washington to help us capture owls when all our trapping efforts were failing. I would like to thank David Arsenault for the use of his Lake Davis, CA study site and use of his field crew to not only capture owls, but also to help with collection of vegetation sampling data. There were so many volunteers and field crew members who worked tirelessly throughout the field work portion of this project and since I could not be in four places at once, they stepped up and helped to collect the information that was needed for this project. I would like to thank my committee Colleen Hatfield, Don Miller, and Jay Bogiatto, for sticking with me long after I should have been finished and contributing their years of experience to help me turn a lot of raw data into a cohesive narrative on the life history of these fascinating birds. Lastly, I would like to thank my partner Julian for sticking by my side during the last 6 years and constantly giving me motivation and words of encouragement whenever I wanted to iv give up. I want to thank my family for supporting me during my long summers camping out in the woods and searching for owls in the middle of the night, and trusting that I wasn’t going to get lost out in the woods. v TABLE OF CONTENTS PAGE Publication Rights ......................................................................................................... iii Acknowledgements ....................................................................................................... iv List of Tables ................................................................................................................. viii List of Figures ............................................................................................................... ix Abstract ......................................................................................................................... xi CHAPTER I. Introduction .................................................................................................. 1 Geolocator Background .................................................................... 1 Flammulated Owl Life History ......................................................... 4 Motivations for this Study ................................................................ 7 II. Methods ......................................................................................................... 9 Study Site Selection .......................................................................... 9 Nighttime Surveys ............................................................................. 14 Nest Checking and Searching ........................................................... 17 Mist-netting and Capture .................................................................. 18 Geolocator Attachment ..................................................................... 19 Recapture .......................................................................................... 21 Vegetation Measurement Methodology ............................................. 22 GIS Analysis ...................................................................................... 27 Statistical Analysis ............................................................................. 29 III. Results ............................................................................................................ 30 Migration Patterns ............................................................................ 30 Estimation of Winter Habitat ............................................................ 39 Breeding Habitat Characterization ................................................... 48 Vegetation Structure ........................................................................ 48 Species Composition ........................................................................ 51 IV. Discussion ...................................................................................................... 53 Geolocators ...................................................................................... 53 Geolocator Routes ............................................................................ 54 vi Timing of Migration ........................................................................ 57 Winter Habitat Selection ................................................................... 64 Breeding Habitat Selection ............................................................... 64 Limitations ........................................................................................ 67 References ..................................................................................................................... 68 Appendix A .................................................................................................................... 79 Appendix B .................................................................................................................... 83 Appendix C .................................................................................................................... 100 vii LIST OF TABLES TABLE PAGE 1. Deployed and Recovered Geolocators from Each Study Site ............................ 30 2. Departure and Arrival Dates for Recovered Flammulated Owls ........................ 38 3. Means, Standard Error, and P-values for Used and Unused Vegetation ............ 49 viii LIST OF FIGURES FIGURE PAGE 1. Flammulated Owl Distribution Map ................................................................... 11 2. Study Site Locations ........................................................................................... 12 3. Overview of Individual Study Areas .................................................................. 13 4. Overview of Lake Davis, CA Study Site ............................................................ 16 5. Close-up of Geolocator Unit ................................................................................ 20 6. Example of Geolocator Attachment .................................................................... 20 7. Geolocator Attachment on Flammulated Owl ..................................................... 21 8. Overlap of Flammulated Owl Territories to Determine Sample Locations......... 24 9. Overview of all Used and Unused Vegetation Sampling Points .......................... 25 10. Vegetation Sampling Plot Set-Up ......................................................................... 27 11. Estimated Migratory Routes for all Recovered Flammulated Owls ..................... 34 12. Estimated Migratory Routes for Pair of CA Owls ................................................ 35 13. Estimated Migratory Routes for Recovered UT Owls .......................................... 36 14. Estimated Migratory Routes for Recovered CO Owls ......................................... 37 15. Kernel Density Polygons for Pair of CA Owls ..................................................... 40 16. Kernel Density Polygons for UT Owls ................................................................. 41 17. 50% Kernel Density Polygons for UT Owls ........................................................ 42 18. Kernel Density Polygons for CO Owls ................................................................ 43 19. Overlay of Land Use Categories on CA 50% Kernel Density Polygons .............. 45 20. Proportion of Vegetation Categories for CA 50% Kernel Density Polygons....... 45 21. Overlay of Land Use Categories on UT 50% Kernel Density Polygons .............. 46 ix 22. Proportion of Vegetation Categories for UT 50% Kernel Density Polygons ....... 46 23. Overlay of Land Use Categories on CO 50% Kernel Density Polygons .............. 47 24. Proportion of Vegetation