SNOWSHOE HARES IN ALASKA. II HOME RANGE AND ECOLOGY DURING AN EARLY POPULATION INCREASE A THESIS Presented to the Faculty of the University of Alaska in Partial Fulfillment of the Requirements for the Degree of Master of Science by Gene R. Trapp Not for Publication Frontispiece. Snowshoe Hare track. February 1962, College, Alaska. Funds for this project came fr Federal Aid In Wildlife Restoration, Alaska Project No. W-6-R-3, and funds contributed by the Alaska Department of Fish and Game. I am sincerely thankful for the direction and counsel given by the following professors at the University of Alaska: Dr. Frederick C. Dean, Head of the Department of Wildlife nagement, Acting Leader of the Cooperative Wildlife Research Unit, nd my major advisor; Dr. Brina Kessel, Head of the Department of Biological Sciences; Dr. James Morrow, Associate Professor of Fisheries; Dr. William • Pruitt, Jr., Associate Professor of Mammalogy; and Dr. L. Gerard Swar z, Assistant Professor of Zoology. I am also Indebted to Dr. Rober B. Weeden, Upland Game Bird Biologist for the Alaska Department f Fish and Game, for his counsel, especially his advice concerning my egetatlon survey; to Dr. Cluff Hopla of the Arctic Aeromedlcal Laboratory (permanently affiliated with the University of Oklahoma) for provldin me with the names of external para­ sites; to Dr. Eleanor Viereck of the Arctic Aeromedlcal Laboratory for aiding me in securing photographs of adult hare genitals; to Dr. Torcom Chorbajian, Assistant Professor of H thematics at the University of Alaska, for help in handling growth ata; and to Hiss Erna Strasbourger, graduate student in the Department o Biological Sciences, for autopsying several hares and providing data on arasites. Peter Dzlklewlcz and Rex Thomas students In the Department of Wildlife Management, contributed val able field assistance and data. I am deeply grateful for the he p of my wife, Carolyn Trapp, who served as field and laboratory assis ant during the sumner and fall of ii 1961. She contributed many logical ideas, spent long hours "'°rktng on Jllustrattons, and critically edited, typed, and retyped the manuscript. iii TABLE OF CONTENTS Page INTRODUCTION • • • • • • • • • • • • • • • • • • • • • • • • • • DESCRIPTION OF STUDY AREA . 4 Location and Geologlcal History • • • • . 4 Climate ••• • • • • • • • . • • • • • • • • • . 4 Vegetat Ion . 8 CENSUS METHODS AND POPULATION DENSITY . .. 10 Ballalne Plot Population Level . • • • • • • 10 Schnabel (Krumholz) Formula . 11 Petersen Ratio • • ••••••••••• • • • • • • 15 Calendar Graph •••••••••••••• . 16 Webb Strip-Census • • • .! • • • • • • . 17 Hartman Toe-clip Ratio. • • . 18 Indices • • • • • • • • . 19 Trap Response and Response to Weather . 21 Interior Alaska Population Level ••• . 27 REPRODUCTION AND DYNAMICS OF THE POPULATION . 31 Sex Ratio •••• . 31 Natality Factors •• . 32 Mortality and Longevity . 37 Predators . 38 Parasites . 39 Other Decimating Factors . • • . 41 HOME RANGE AND MOVEMENTS • • • • • . 42 tv Page Home Range • • • • 42 Range Length • • • • • • • • 51 Movements • • • • • • • 51 BEHAVIOR • • • • • • • 53 Use of Forms and Burrows • • • • 53 Votce and Thumping • • • • • • • • • 57 Agonlstle and lnvesttgatfve Behavior • • 60 Use of Runways • • . • • • 62 Hare "Nests" and Behavior of Young • ••• • 63 Food Habf ts • • • • • • • • • • • • • • • • • • 69 PELAGE CHANGE • • • • • • • • • • • • • • • 73 AGE DETERMINATION • • • • • • • • • 76 Hf nd-Foot Color • • • • • • • • • • • 76 Eplphyseal Groove Closure • • • 76 Genftal Morphology • . ... 77 Body Weight • • • • • • • 83 Hind-Foot Length • • • 86 Lens Weight • • • • • 88 SUMMARY • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 94 LITERATURE CITED • • • • • • • • • • • • • • • • • 98 APPENDIX • • • • • • • • • • • 103 v LIST OF ILLUSTRATIONS Figure Page 1• Location of the Ba11alne study area •• . 5 2. Fairbanks temperature and precipitation regimes, June 1960 through November 1961 ••••••••• . 6 3. Vegetation stands and trap sites on the Ba11alne study area • • • • • • • • • • • • • • • • • • • . 9 4. Live-trap situated In a hare runway •• • • . 12 5. TWo methods of outlining home ranges for size measurement • • • • • • • • • • • • • • • • • . 44 6. Willows and small spruces bent to the ground by qall . 55 1. A bent-over alder completely covered by qall . 55 8. A qamanlq under a black $pruce •••• . 56 9. Whlte\:;tpruce-wl11ow-alder stand where a hare "nest" with young was found In June, 1961 ••••••••• . 64 10. Hollow under a brush pile where 1everets were found • . 64 11. Form under a Shepherdla shrub, where six young were born on 3 July 1961 •••••••••••••••• • • • • 66 12. Form under a small white spruce, where six young were born on 5 July 1961 •••••••••••• . 66 13. Leverets less than 24 hrs. old In the form where they were born • • • • • • • • • • • • • • • • • • • • . 68 14. Small leveret among the leaves . 68 15. Comparison of vegetation inside and outside hare pen . 70 16. Brush pile, mostly willows, debarked by hares •• • • . 70 17. Pelage phenology of hares In Interior Alaska, and in Wisconsin and Maine • • • • • • • • • • •• . 74 18. Juvenile hare penis • . 79 19. Adult hare penis . 79 20. Juvenile hare vulva •• . 80 21. Adult hare vulva . 80 vi Figure Page 22. Transitional hare pents . 82 23. Increase in body weight in Interior Alaska hares •• • • 85 24. Increase in hind-foot length In Interior Alaska hares • • • • • • • • • • • • • • • • • • • • • • • • • . 87 25. Lens growth In Interior Alaska hares • • • • • • • • • • • 92 26. Symbols used to depict vegetation •• • • • • • • . 104 27. Graph of Stand A • • • • . • • . • • 108 28. Photograph of Stand A • • • • . • • • . 110 . 29. Graph of Stand B • • • • • • • . • • • • • • • • • • • 112 to. Photograph of Stand B • • • • . • • . 114 31. Graph of Stand C . 115 32. Photograph of Stand C • • • • • • • • • • • • . 117 33. Graph of Stand 0 • • • • . • • • • • • • • • • • • • 118 34. Photograph of Stand 0 • • • • • • • . • • • • • • 120 35. Graph of Stand E • • • • • • • • . 121 36. Photograph of Stand E • • • . 123 37. Graph of Stand F • • . • • . • • • . 125 38. Photograph of Stand F • . 127 39. Graph of Stand G • • • . 128 4o. Photograph of Stand G . 130 41. Graph of Stand H • • • . 131 42. Photograph of Stand H • • • .• . • • • . • • • • • . • • 133 43. Graph of Stand I . • • • • • • • • • . 134 44. Photograph of Stand I • . ·• . 136 vir LIST OF TABLES Table Page t • Mean monthly snow depths on the Ballafne study area . 7 2. Apparent trap avoidance Jn hares on the Ballaine study area, College, Alaska ••••••••••• . 13 3. Estimates of hare populations on the Ballaine study area, using the Schnabel (Krumholz) formula ••••• • • • • 14 4. Number of runways and fndfvldual hare tracks crossing tNO one-half mile transects on the Ballalne study area, College, Alaska •••••••••••••••• . 20 5. Monthly trap success and recapture success, Hay 1960 to November 1961 •••••••••••••••••• • • • • 23 6. Sex and age ratios of hares caught at College, Alaska from Hay 1960 to November 1961 • • • • • • • • • • • • • • • 26 7. Response to weather: number of hares captured following nights of inclement weather, Ballaine study area, College, Alaska •••••••••• . 28 8. Snowshoe Hare I I tter .size and frequency In North AIJter f ca • • • • • • • • • • • • • • • • • • • • . 34 Average number of litters/female hare season, calculated by Green and Evans' (1940c) formula, for College, Alaska •••••••••••••• • • • • • • • 36 10. Recapture data collected from May 1960 to November 1961 on the Ballaine study area, College, Alaska . 46 11. Recapture data collected from April 1959 to April 1960 on the Ballafne study area, College, Alaska . 49 12. Closure of the epiphyseal groove in Interior Alaska Snowshoe Hares • • • • • • • • • • • • • • • • • • • • . 78 13. Lens growth f n Snowshoe Hares •••• . • • 89 14. Species of plants comprising the physlognomlc categories in vegetation stands on the Ballafne study area, College, Alaska •••••••••••• • • • 105 15. Vegetation coverage In Stand A . 109 16. Vegetation coverage In Stand 8 . 113 vi ft Table Page 17. Vegetation coverage In Stand C • • • • • •. • . • . • • . • 116 18. Vegetation coverage In Stand D • . • • • • • . • • • • • 119 19. Vegetation coverage In Stand E • • • • • • • • • • • • • • • 122 20. Vegetation coverage In Stand F • . • • • • • • • • • • • • • 126 21. Vegetation coverage In Stand G • • • • • . • • • • • • • • • 129 22. Vegetation coverage In Stand H • • • • • . • • • • • . • . • 132 23. Vegetation coverage in Stand I • • • • • • • • • • • • • • . 135 Ix ABSTRACT A segment of 1 continuing study of Snowshoe. Rares was conducted from May 196o to November 1961, near College, Alaska. ObjectJves regarding home range, reproduction, behavior, 1ge-determfn1tfon criteria, and census methods were achieved by 11ve-trappJng and snaring. \ The Schnabel (Krumholz) formula and Petersen ratio for estimating population size were fnva1Jdated by differential trap response. The calendar graph, Webb strip-census, Hartman toe-clip ratJo, pellet count, and road survey all proved poor or useless as used durJng. this ltudy for estimating hare abundance In this area. An Increase in hare sign In marginal habitat between 1958 and 1961 Indicated an increase fn popu­ latfon density. Solle hares were caught many tl11es In succession Jn the same trap. Many more avoided traps, some for periods of nearly two years. Inclement weather restricted movements of hares. Adult and juvenile sex ratios were 1:1. The season of births extended from mid-May to