SPECIES ASSESSMENT FOR SAGE THRASHER (OREOSCOPTES MONTANUS ) IN WYOMING prepared by 1 2 1 REBECCA S B USECK , DOUGLAS A. K EINATH , AND MATTHEW H. M CGEE 1 Wyoming Natural Diversity Database, University of Wyoming, 1000 E. University Ave, Dept. 3381, Laramie, Wyoming 82071; 307-766-3023 2 Zoology Program Manager, Wyoming Natural Diversity Database, University of Wyoming, 1000 E. University Ave, Dept. 3381, Laramie, Wyoming 82071; 307-766-3013; [email protected] prepared for United States Department of the Interior Bureau of Land Management Wyoming State Office Cheyenne, Wyoming December 2004 Buseck, Keinath, and McGee – Oreoscoptes montanus December 2004 Table of Contents SUMMARY .......................................................................................................................................... 3 INTRODUCTION ................................................................................................................................. 3 NATURAL HISTORY ........................................................................................................................... 4 Morphological Description ...................................................................................................... 4 Taxonomy and Distribution ..................................................................................................... 6 Habitat Requirements............................................................................................................. 8 General .............................................................................................................................................8 Breeding ...........................................................................................................................................8 Nonbreeding.....................................................................................................................................9 Foraging .........................................................................................................................................10 Area Requirements.........................................................................................................................10 Landscape Context .........................................................................................................................11 Movement and Activity Patterns ............................................................................................11 Dispersal.........................................................................................................................................11 Migration........................................................................................................................................12 Daily Activity.................................................................................................................................13 Reproduction and Survivorship..............................................................................................14 Breeding Behavior..........................................................................................................................14 Nest-Building .................................................................................................................................15 Breeding Phenology .......................................................................................................................16 Fecundity and Survivorship............................................................................................................17 Population Demographics......................................................................................................18 Limiting Factors .............................................................................................................................18 Metapopulation Dynamics and Genetic Concerns .........................................................................18 Food Habits...........................................................................................................................18 Diet.................................................................................................................................................18 Foraging Strategy ...........................................................................................................................19 Foraging Variation .........................................................................................................................19 Community Ecology...............................................................................................................20 Competitors and Predators .............................................................................................................20 Parasites and Disease......................................................................................................................22 Symbiotic and Mutualistic Interactions..........................................................................................23 CONSERVATION .............................................................................................................................. 23 Conservation Status ..............................................................................................................23 Federal Endangered Species Act....................................................................................................23 Bureau of Land Management.........................................................................................................24 Forest Service.................................................................................................................................24 State Wildlife Agencies..................................................................................................................24 Natural Heritage Ranks ..................................................................................................................25 Partners In Flight Priority List........................................................................................................26 Biological Conservation Issues..............................................................................................26 Abundance and Abundance Trends................................................................................................26 Population Connectivity and Habitat Trends .................................................................................28 Range Context................................................................................................................................30 Extrinsic Threats ............................................................................................................................30 Invasive Species...........................................................................................................................31 Page 1 of 72 Buseck, Keinath, and McGee – Oreoscoptes montanus December 2004 Agricultural Practices...................................................................................................................32 Fire ...............................................................................................................................................34 Urban and Natural Resource Development..................................................................................35 Recreation ....................................................................................................................................36 Stochastic Factors (e.g., weather events) .....................................................................................37 Natural Predation .........................................................................................................................37 Intrinsic Vulnerability ....................................................................................................................38 Habitat Specificity and Fidelity....................................................................................................38 Territoriality and Area Requirements ..........................................................................................38 Susceptibility to Disease ..............................................................................................................39 Dispersal Capability.....................................................................................................................39 Reproductive Capacity.................................................................................................................39 Sensitivity to Disturbance ............................................................................................................40 Genetic Factors.............................................................................................................................41 Population Viability Analyses........................................................................................................41 Protected Areas ..............................................................................................................................42 CONSERVATION ACTION ................................................................................................................ 42 Existing or Future Conservation Plans...................................................................................42