The ecology of the American badger Taxidea taxus in California: assessing conservation needs on multiple scales. By JESSICA HELENE QUINN B.S. (University of California, Santa Barbara) 1998 M.S. (University of California, Davis) 2004 DISSERTATION Submitted in partial satisfaction of the requirements for the degree of DOCTOR OF PHILOSOPHY in Ecology in the OFFICE OF GRADUATE STUDIES of the UNIVERSITY OF CALIFORNIA DAVIS Approved: Committee in Charge 2008 i UMI Number: 3317963 INFORMATION TO USERS The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleed-through, substandard margins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. 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Eisenhower Parkway PO Box 1346 Ann Arbor, Ml 48106-1346 TABLE OF CONTENTS Acknowledgements iii List of Tables vii List of Figures ix Abstract 1 Introduction 3 Chapter 1: Activity-specific habitat preferences of badgers {Taxidea taxus) in coastal California 30 Chapter 2: Factors affecting the movement behavior of American badgers {Taxidea taxus) 72 Chapter 3: Investigating changes in the range extent of American badgers in California {Taxidea taxus) using sightings data 105 Summary 148 Appendix A: Mortality related to an implanted abdominal radio transmitter in an American badger {Taxidea taxus) 168 Appendix B: A serological survey and anticoagulant screen of American badgers {Taxidea taxus) at the urban-wildland interface 183 Appendix C: A comparison of monitoring methods for American badgers 196 Appendix D: Consideration and coverage for American badgers in current (2007) versions of regional conservation plans in California 199 ii ACKNOWLEDGEMENTS Funding and support for this research was generously provided by the California Department of Fish and Game/UC Davis Wildlife Health Center Resource Assessment Program; the American Wildlife Research Foundation; the American Society of Mammalogists; the American Museum of Natural History's Theodore Roosevelt Memorial Grant Program; the Western Section of the Wildlife Society; the Chuck Haugen Conservation Foundation; UC Davis Jastro-Shields Graduate Research Grants; and Block Grant Fellowships from the UC Davis Ecology Graduate Group. I wish to express my sincerest gratitude to my advisor, Rosie Woodroffe, for musing during our first meeting together, "Hmm... what about badgers?" Her incredible enthusiasm for carnivores, and her complete confidence in my abilities were instrumental in my undertaking and completing this project. Rosie also provided insightful mentorship and advice when I was particularly challenged by the rigors of solely managing a large project. I feel very lucky to have had the opportunity to learn from such an accomplished and passionate conservation researcher. Special thanks to Mark Schwartz, for serving on my orals committee and dissertation committee. Mark truly went above and beyond—supporting my independent study of landscape ecology, brainstorming analysis ideas for a somewhat problematic dataset, and even stepping in to escort me through graduation ceremonies. I am impressed by and grateful for Mark's unwavering commitment to the students of the Graduate Group in Ecology. Thanks too to Steve Greco, who also served on my orals and dissertation committee. Steve selflessly devoted his complete attention to our sometimes multi-hour meetings; and his enthusiasm for conservation in California, iii particularly in the Central Valley, was infectious. I have been so inspired by his aoility to address land-use management issues with his research. I would also like to thank Dirk Van Vuren for his assistance as I stumbled through the administrative aspects of my project, and for sharing badger stories of his own with me. My lab-mates, Hilary Swarts, Rachel Mazur, Matt Swarner, and Katie Prager helped me maintain my sense of humor. Christine Kreuder-Johnson, Steve Torres, and Eric Loft were instrumental in developing this project. Collaborating with Chris and Kirsten Gilardi was a wonderful experience; it is rare to find as energetic, collaborative and productive a team as exists at the Wildlife Health Center! My sincere thanks also tq Mike Murray, Dave Jessup, Amy Wells, Sue Campbell, everyone at Avian and Exotics Veterinary Clinic, and all the staff at the Marine Wildlife Veterinary Care and Research Center in Santa Cruz for being at beck and call for badger surgeries. Thanks too to Dale Steele and Esther Burkett at CDFG for assistance with the Species Status Report. I feel so lucky to have encountered the amazing group of people in Shannon Bros's lab at San Jose State University, particularly when I was feeling somewhat isolated in my trailer in the wilds. Thanks so much to Shannon for offering guidance, advice, insight, and friendship from the moment I met her. Chris Lay truly laid the foundation for what became my dissertation, and all badger researchers in California that follow should be grateful for his pioneering work in field. I also enjoyed getting to know Chrissie Klinkowski, Leslee Parr, and Mary Poffenroth both professionally and unprofessionally! Thanks to Rick Hopkins for advice along the way. Finally, very special thanks to my colleague and collaborator, Tanya Diamond. Tanya's unfailing optimism and assistance truly carried me through much of this project. It has been such a iv privilege to have found such an incredible fellow badger researcher, and I'm glad to have had the opportunity to take this journey together. Bruce Delgado is truly a force of nature. Without his advocacy and assistance, this project would never have been possible. I thank him for introducing me to the Fort Ord community, and for his continued excitement about badgers and conservation. The members of the BLM Fort Ord Field Station graciously hosted my stay in their backyard, and made me feel so welcomed. Dairen Simpson has forgotten more than I will ever know about trapping. I am honored to have had the opportunity to glean even the smallest amount of his knowledge. I look forward to the next time we work together in the field, and hope he can manage to be at least a little bit funny this time. Thanks to all my assistants and interns: Geriann Albers, John Clare, Johanna Davis, Bruce Delgado, Tanya Diamond, Jessica Dunlap, Mark Elbroch, Janel Fishpaw, Tim Fullman, Jessica Gist, Kimberley Greeson, Andrew Hida, Colin Hoisington, Daniel Jackson, Tammy Jakl, Marina Kasa, Courtney McSherry, Vivian Nelson, Mary Paul, Patt Quinn-Davis, Alyssa Stark, Patrick Switzer, Nicole Tautfest, Brett Williams, Topo, and the BLM Fort Ord Field Station Volunteers. They were absolutely amazing. I could never have done any of this without them. Many agencies allowed me on their land to scout for badgers, for which I am also sincerely grateful: BLM Hollister Office (Fort Ord Field Station), Sierra Foothills Conservancy, Sequoia Riverlands Trust, Sacramento Valley Conservancy, Pacheco State Park, BLM Carrizo Plain Natl. Monument, US Army National Guard Camp Roberts, City of San Luis Obispo, NPS Point Reyes National Seashore, Big Sur Land Trust, the Las Palmas Development, and the UC Natural Reserve System. v Finally, my love and thanks to my family and friends for supporting me through this long journey. My friends were endlessly tolerant of my somewhat flaky tendencies, and never failed to keep me humble. I am especially indebted to my wonderful friends at Zuda, for helping me find a way to balance it all and to truly be happy while doing it! The amazing family that raised me: Mom and Dad, Kate, Mary Jo, Tommy and Julie, Lou, Connie, Julie and Pete, Jack and Dorothy, Kathy and Chip.. .each and every one of them played a role in creating the person I've become. Thanks to my parents who have always encouraged and trusted me. Their support has allowed me to live this adventure. Thanks and love to my sister Jo, who will someday go backpacking with me, and to all of the rest of my family. I am especially grateful to Brett, for just about everything. He encourages and inspires me in just about every way that makes me a better person. And honestly, there is simply no one more fun to hang out with. Except perhaps Topo. Thanks, Topo. I would like to dedicate this dissertation to my mom, who taught me by her example. I hope I can be the same inspiration for little what's-her-name. vi LIST OF TABLES Table 1.1: Summary of radio-tracking data collected for Taxidea taxus, Fort Ord Public Lands, California 46 Table 1.2: Habitat rankings for Taxidea taxus comparing composition of home ranges to that of the study site (second-order preference) 49 Table 1.3: Contingency table of relationships between preferred habitat classes for Taxidea taxus (significant different in paired t-tests for home ranges within the study site); percent of points, and expected vs. observed number of points, in each pair of classes 50 Table 1.4: Habitat rankings for Taxidea taxus comparing composition of active locations to that of the home range (third-order preference) 51 Table 1.5: Contingency table of relationships between preferred habitat classes for Taxidea taxus (significant different in paired t-tests for active locations within the home range); percent of points, and expected vs. observed number of point, in each pair of classes 51 Table 1.6: Habitat rankings for Taxidea taxus comparing composition of den locations to that of the home range (third-order preference) 53 Table 1.7: Contingency table of relationships between preferred habitat classes for Taxidea taxus (significant different in paired t-tests for den locations within the home range); percent of points, and expected vs.