University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1974 Distribution and population characteristics of bighorn sheep near Thompson Falls in northwestern Montana Gerald Warren Brown The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Brown, Gerald Warren, "Distribution and population characteristics of bighorn sheep near Thompson Falls in northwestern Montana" (1974). Graduate Student Theses, Dissertations, & Professional Papers. 6510. https://scholarworks.umt.edu/etd/6510 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. DISTRIBUTION AND POPULATION CHARACTERISTICS OF BIGHORN SHEEP NEAR THOMPSON FALLS IN NORTHWESTERN MONTANA By Gerald W. Brown B. A ., University of California at Riverside, 1970 Presented in partial fulfillment of the requirements for the degree of Master of Science UNIVERSITY OF MONTANA 1974 Approved by: Chairman, Board of Examiners Dean/ Graduate School ! i 7 r Date UMI Number: EP37311 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMT OisjWMlâtiofi PuWishing UMI EP37311 Published by ProQuest LLC (2013). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code P roQ ^sf ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106 - 1346 ACKNOWLEDGMENTS I am especially grateful to Dr. Bart W. O’Gara, major advisor for this project, for assistance and guidance throughout this study and for critical review of the manuscript. Thanks are also due other members of the committee, Drs. P. L. Wright and Bob Ream, and Mr. R. P. Weckwerth for review of the thesis. Dr. Lee Metzgar provided helpful suggestions on inter­ pretation of population data. Gary Halvorson, Jack Fisher, and Dick Smith of the U. S. Forest Service, Lolo National Forest, provided helpful graphic m a te r ia ls. I appreciate the cooperation, use of equipment, and flight time provided by the Montana Fish and Game Department. My wife, Chris, assisted with some of the trapping and provided the patience and understanding sorely needed during this study. My brother-in-law. Bill Unbehend, also helped with some of the trapping. Numerous others helped in various ways, and to them I say thanks. Financial support for this project came from the Montana Cooperative Wildlife Research Unit (U. S, Fish and Wildlife Service, University of Montana, Montana State Fish and Game Department, and Wildlife Management Institute cooperating). ii TABLE OF CONTENTS P age LIST OF TABLES ............................................................................................ v i LIST OF FIGURES ............................................................................................ v iii CHAPTER I. INTRODUCTION ........................................................................ 1 II. DESCRIPTION OF THE STUDY AREA .... 6 L o c a t i o n ................................................................................... 6 G e o l o g y ................................................................................... 6 Land U s e ................................................................................... 9 C l i m a t e ................................................................................... 10 V e g e t a t i o n ............................................................................. 13 III. MATERIALS AND METHODS............................................... 21 T r a p p in g ................................................................................... 21 Group F i d e l i t y ....................................................................... 26 Winter Centers of A ctivity............................................. 26 P a r a s it e s 2 7 Food Habits 2 7 C ensus in g ................................................................................... 28 O b serv a tio n s 2 9 IV. RESULTS ........................................................................................... 31 T r a p p in g ................................................................................... 31 Salt Lick U tilization .......................................................... 34 C o l l a r s ................................................................................... 37 C o n d itio n ................................................................................... 38 D e m o g r a p h y............................................................................. 38 Population s e g m e n t s .................................................... 38 Population e s t i m a t e s .................................................... 39 111 Page A g e-se x c o m p o s it io n .................................................... 42 Survivorship ....................................................................... 45 Group size and com position ....................................... 45 Group fid elity ................................................................ 49 Distribution and Movements ............................................. 51 Winter range ....................................................................... 51 Winter centers of a c tiv ity ....................................... 60 Spring range ....................................................................... 62 L a m b in g ............................................................................. 63 Summer ran ge ................................................................ 63 Summer activity centers............................................. 64 F a ll r a n g e ....................................................................... 66 Habitat u s e ....................................................................... 67 Diseases and P arasites................................................... 67 Lung an alyses................................................................ 71 Ectoparasites ................................................................ 71 P r e d a tio n ................................................................................... 73 A c c id e n ts ................................................................................... 74 Food H abits ............................................................................. 75 Horn Growth ............................................................................. 79 V. DISCUSSION AND RECOMMENDATIONS .... 83 T r a p p in g ................................................................................... 83 Salt lick utilization.......................................................... 84 C o l l a r s ............................................................................. 85 C o n d itio n ............................................................................. 86 D e m o g r a p h y............................................................................. 89 Population segm ents ................................................... 89 Age-sex com position ................................................... 90 Group size and composition ....................................... 92 Group fid e lity ................................................................ 93 Distribution and Movements ............................................. 94 Winter range ....................................................................... 95 Winter centers of a c tiv ity ....................................... 95 Spring range ....................................................................... 96 L a m b in g ............................................................................. 97 Summer ran ge ................................................................ 97 Summer centers of activity....................................... 98 F a ll r a n g e ....................................................................... 100 Diseases and P arasites.................................................... 100 Population Regulation .......................................................... 103 iv Page Food H abits ............................................................................. 104 Horn Growth ............................................................................. 106 Management O ptions .......................................................... 108 Natural population regulation ................................ 108 Three-fourths horn harvest ....................................... 109 Trophy ram s....................................................................... 109 Maximum productivity............................................. 109 VI. SUMMARY ..................................................................................... I l l LITERATURE CITED ..................................................................................