NESTING ECOLOGY OF THE EASTERN BOX TURTLE (TERRAPENE CAROLINA CAROLINA) IN A FRAGMENTED LANDSCAPE by Rebecca Lynn Kipp A thesis submitted to the Faculty of the University of Delaware in partial fulfillment of the requirements for the degree of Master of Science in Entomology and Applied Ecology Summer 2003 Copyright 2003 Rebecca Lynn Kipp All Rights Reserved NESTING ECOLOGY OF THE EASTERN BOX TURTLE (TERRAPENE CAROLINA CAROLINA) IN A FRAGMENTED LANDSCAPE by Rebecca Lynn Kipp Approved: __________________________________________________________ Jacob L. Bowman, Ph.D. Professor in charge of thesis on behalf of the Advisory Committee Approved: __________________________________________________________ Douglas W. Tallamy, Ph.D. Chair of the Department of Entomology and Wildlife Ecology Approved: __________________________________________________________ Robin W. Morgan, Ph.D. Dean of the College of Agriculture and Natural Resources Approved: __________________________________________________________ Conrado M. Gempesaw II, Ph.D. Vice Provost for Academic Programs and Planning ACKNOWLEDGMENTS Many thanks to Dr. Jacob Bowman, who gave me the opportunity to conduct my Master’s research on turtles and provided much encouragement and assistance over the past 3 years. I also thank him for reading many revisions of my thesis and always taking time to help improve my writing. I thank Nathan Nazdrowicz sharing his knowledge of box turtles and nesting ecology and for being such a great help with my research. I thank all the undergraduate research assistants who devoted their time and energy to this project, including Jordona Doughty, Raymond Iglay, Rebekah Baity, Isabelle Lajoie, Adam Porter, and Christopher Howey. I thank the New London Veterinary Center for conducting x-rays at a reduced rate in 2001. I thank Tri-State Bird Rescue and Research for donating the use of their equipment in 2002, and Andrea Howey for volunteering her time to conduct x-rays. I also thank my committee members Drs. Roland R. Roth, Donald C. Forester, and Douglas W. Tallamy for taking the time to serve on my committee. I thank the Delaware Division of Parks and Recreation for allowing access to White Clay Creek State Park and waiving park entrance fees. I also thank the Frederick family for encouraging this research project and allowing us full access to the Turkey Run property. Funding support was provided by the MacIntire-Stennis Cooperative Forestry Program. iii Lastly, I thank my parents for helping me pursue my dreams and always providing their help and encouragement. Without their support, I would not have been able to take my time in deciding which direction to go with my life. Thanks also to Kristopher Pickard for spending endless hours in the field, staying up late at night with nesting turtles, and giving me all the support and encouragement I needed to make it through the longest 3 years of my life. iv TABLE OF CONTENTS LIST OF TABLES .......................................................................................................vii LIST OF FIGURES.......................................................................................................ix ABSTRACT ..................................................................................................................xi INTRODUCTION……………………………………………………………………..1 Nest Site Selection………………………………………………………...2 Clutch Frequency………………………………………………………….4 Survivorship……………………………………………………………….5 Objectives…………………………………………………………………6 STUDY AREAS……………………………………………………………………….8 University of Delaware Woodlot………………………………………...12 University of Delaware Webb Farm Woodlot…………………………...15 Turkey Run Property…………………………………………………….17 White Clay Creek State Park…………………………………………….19 METHODS…………………………………………………………………………...22 Capture and Marking…………………………………………………….22 Radiotelemetry…………………………………………………………...23 Nesting…………………………………………………………………...25 Nest Site Selection……………………………………………………….26 Analyses………………………………………………………………….28 RESULTS…………………………………………………………………………….31 Nesting Behavior………………………………………………………...33 v Clutch Size and Frequency………………………………………………36 Nest Site Selection……………………………………………………….40 Nest Success…………………………………………………………..…48 Nest Site Fidelity………………………………………………………...55 Incubation Period and Hatchling Emergence……………………………56 DISCUSSION………………………………………………………………………...58 Nesting Behavior………………………………………………………...59 Clutch Size and Frequency………………………………………………61 Nest Site Selection……………………………………………………….62 Nest Success……………………………………………………………..66 Nest Site Fidelity………………………………………………………...68 Incubation Period and Hatchling Emergence……………………………69 Management Implications……………………………………………….70 LITERATURE CITED……………………………………………………………….73 vi LIST OF TABLES Table 1. Average monthly minimum and maximum temperatures and total monthly precipitation for the 2001 – 2002 field seasons in Newark, Delaware (National Oceanic & Atmospheric Administration 2001, 2002)……..…11 Table 2. A summary of egg-laying behavior for the 2001 – 2002 field seasons for eastern box turtles in 4 populations in northern Delaware………………35 Table 3. A summary of timing of nesting behavior at 39 eastern box turtle nests on 4 study areas in northern Delaware during the 2001 - 2002 field seasons…………………………………………………………………...37 Table 4. Clutch size of eastern box turtles by study area during the 2001 – 2002 field seasons in northern Delaware………………………………………41 Table 5. The relationship of morphometric measurements to clutch size of female eastern box turtles in northern Delaware during the 2001 – 2002 field seasons…………………………………………………………………...42 Table 6. Distances eastern box turtle females moved (m) during the 2001 and 2002 field seasons at 4 study areas in northern Delaware. Distances moved differed among study sites (F3, 33 = 15.40, P < 0.001)………………..….43 Table 7. Summary of microhabitat characteristics for 39 eastern box turtle nests and random plots on 4 study sites in northern Delaware during 2001 and 2002. A paired t-test was used to detect differences between nests and random plots……………………………………………………………..49 Table 8. Summary of microhabitat characteristics for 39 eastern box turtle nests at nesting, 1 month after nesting, and 2 months after nesting in northern Delaware during 2001 – 2002. A repeated measures ANOVA was used to detect differences in variables across time…………………………….....50 Table 9. Eggs hatched for each successful nest in the 2001 – 2002 field seasons during an eastern box turtle study in northern Delaware………………...52 vii Table 10. Timing of predation for eastern box turtle nests in northern Delaware for the 2001 – 2002 field seasons…………………………………………..54 Table 11. Estimated incubation length (in days) for eastern box turtle nests in northern Delaware for the 2001 – 2002 field seasons………….……….57 viii LIST OF FIGURES Figure 1. Aerial photograph (1997) showing proximity of eastern box turtle populations at the University of Delaware Webb Farm Woodlot (top) and University of Delaware Woodlot (bottom) study areas in Newark, Delaware during 2001 - 2002……………………………………….……..9 Figure 2. Aerial photograph (1997) showing proximity of eastern box turtle populations at Turkey Run Property (top) and White Clay Creek State Park (bottom) study areas in Newark, Delaware during 2001 – 2002…………10 Figure 3. Aerial photograph (1997) of the University of Delaware Woodlot in Newark, Delaware used during 2001 – 2002 for an eastern box turtle study……..………………………………………………………………...13 Figure 4. Aerial photograph (1997) of the University of Delaware Webb Farm Woodlot in Newark, Delaware used during 2001 – 2002 for an eastern box turtle study………………………………………………………………...16 Figure 5. Aerial photograph (1997) of the Turkey Run Property in Newark, Delaware used during 2001 – 2002 for an eastern box turtle study………………….18 Figure 6. Aerial photograph (1997) of an interior portion of White Clay Creek State Park in Newark, Delaware used during 2001 – 2002 for an eastern box turtle study………………………………………………………………...20 Figure 7. The number of gravid eastern box turtles by week for the 2001 and 2002 field seasons in northern Delaware. Data were based on x-ray results and known nesting dates. X-rays were not conducted until the first week of June in 2001……………………………………………………………….32 Figure 8. Range of clutch sizes of female eastern box turtles during the 2001 and 2002 field seasons in northern Delaware……………………………..39 Figure 9. Eastern box turtle nest locations at White Clay Creek in Newark, Delaware for the 2001 – 2002 field seasons. Circles represent 2001 nests and squares represent 2002 nests………………………………………………………44 Figure 10. Eastern box turtle nest locations at Turkey Run in Newark, Delaware during the 2001 – 2002 field seasons. Circles represent 2001 nests and squares represent 2002 nests. Circled nests are from a female that nested in the same location in consecutive years………………………………...45 ix Figure 11. Eastern box turtle nest locations at Webb Farm in Newark, Delaware during the 2001 – 2002 field seasons in northern Delaware. Circles represent 2001 nests and squares represent 2002 nests. Circled nests are from a female that nested in the same location in consecutive years…..…46 Figure 12. Eastern box turtle nest locations at the UD Woodlot in Newark, Delaware during the 2001 – 2002 field seasons. Circles represent 2001 nests and squares represent 2002 nests. Circled nests are from a female that nested in the same location in consecutive years. Nest in upper left- hand corner is shown with an arrow……………………………………...47 x ABSTRACT A paucity of information is available on the nesting ecology