Yellowstone Grizzly Bear Investigations 2011 Report of the Interagency Grizzly Bear Study Team Photo courtesy of Gary Pollock Data contained in this report are preliminary and subject to change. Please obtain permission prior to citation. To give credit to authors, please cite the section within this report as a chapter in a book. Below is an example: Cain, S. 2012. Grand Teton National Park recreational use. Page 45 in F.T. van Manen, M.A. Haroldson, and K. West, editors. Yellowstone grizzly bear investigations: annual report of the Interagency Grizzly Bear Study Team, 2011. U.S. Geological Survey, Bozeman, Montana, USA Cover photo: Bear 610 watches as one of her cubs climbs a tree. See “Cub Adoption Documented in Grand Teton National Park.” Photo courtesy of Gary Pollock. YELLOWSTONE GRIZZLY BEAR INVESTIGATIONS Annual Report of the Interagency Grizzly Bear Study Team 2011 U.S. Geological Survey Wyoming Game and Fish Department National Park Service U.S. Fish and Wildlife Service Montana Fish, Wildlife and Parks U.S. Forest Service Idaho Department of Fish and Game Eastern Shoshone and Northern Arapaho Tribal Fish and Game Department Edited by Frank T. van Manen, Mark A. Haroldson, and Karrie West U.S. Department of the Interior U.S. Geological Survey 2012 Table of Contents INTRODUCTION ............................................................................................................................................. 1 This Report ............................................................................................................................................ 1 History and Purpose of the IGBST ........................................................................................................ 2 Previous Research .................................................................................................................................. 3 RESULTS AND DISCUSSION ......................................................................................................................... 4 Bear Monitoring and Population Trend ................................................................................................. 4 Marked Animals ......................................................................................................................... 4 Assessing Trend and Estimating Population Size from Counts of Unduplicated Females ................................................................................................................ 10 Cub Adoption Documented in Grand Teton National Park ....................................................... 16 Occupancy of Bear Management Units by Females with Young .............................................. 18 Observation Flights .................................................................................................................... 19 Telemetry Relocation Flights ..................................................................................................... 22 Estimating Sustainability of Annual Grizzly Bear Mortalities .................................................. 23 Key Foods Monitoring........................................................................................................................... 29 Spring Ungulate Availability and Use by Grizzly Bears in Yellowstone National Park ............................................................................................................................. 29 Spawning Cutthroat Trout .......................................................................................................... 32 Grizzly Bear Use of Insect Aggregation Sites Documented from Aerial Telemetry and Observations ...................................................................................................... 36 Whitebark Pine Cone Production ............................................................................................... 39 Use of Diminished Whitebark Pine Resources by Adult Female Grizzly Bears in the Taylor Fork Area of the Gallatin National Forest, Montana, 2011 .................................. 41 Habitat Monitoring ................................................................................................................................ 45 Grand Teton National Park Recreational Use ............................................................................ 45 Yellowstone National Park Recreational Use ............................................................................ 46 Trends in Elk Hunter Numbers within the Grizzly Bear Recovery Zone Plus the 10-mile Perimeter Area ................................................................................................ 47 Grizzly Bear-Human Conflicts in the Greater Yellowstone Ecosystem ................................................ 48 LITERATURE CITED ....................................................................................................................................... 53 Appendix A: Monitoring Whitebark Pine in the Greater Yellowstone Ecoregion: 2011 Annual Report Summary ................................................................................................................................... 60 Appendix B: 2011 Grizzly Bear Habitat Monitoring Report ................................................................. 66 regard to potential impacts of whitebark pine (Pinus albicaulis) decline on grizzly bears and vacated the Introduction delisting rule (Greater Yellowstone Coalition v. State th (Mark A. Haroldson and Frank T. van Manen, of Wyoming, No. 09-36100 [9 Cir. 2011]). Although Interagency Grizzly Bear Study Team) the change in status was upheld, we continue to follow monitoring protocols established under the This Report Revised Demographic Recovery Criteria (USFWS This Annual Report summarizes results of 2007b) and the demographic monitoring section of the grizzly bear (Ursus arctos horribilis) monitoring Final Conservation Strategy for the Grizzly Bear in and research conducted in the Greater Yellowstone the Greater Yellowstone Area (USFWS 2007c). The Ecosystem (GYE) by the Interagency Grizzly Bear IGBST will continue reporting on an array of required Study Team (IGBST) during 2011. The report monitoring programs. These include both population also contains a summary of nuisance grizzly bear and habitat components. Annual population management actions. monitoring includes: The IGBST continues to work on research • Monitoring unduplicated females with COY questions associated with counts of unduplicated and estimating total population size for the females with cubs-of-the-year (COY). These counts entire GYE based on the model-averaged are used to estimate population size, which are then Chao2 estimate of females with COY (see used to establish annual mortality limits. Previous “Assessing Trend and Estimating Population research demonstrated these counts are biased low Size Using Counts of Unduplicated Females”). so the IGBST examined alternative techniques to • Monitoring the distribution of females with estimate the number of unduplicated females with young of all ages and having a target of at least COY. Results of an investigation into an approach 16 of 18 Bear Management Units (BMUs) using sequential clustering of female with COY within the Recovery Zone (i.e., Primary sightings combined with Bayesian methods and Conservation Area (PCA)) occupied at least 1 ancillary data resampling was presented at a workshop year in every 6, and no 2 adjacent BMUs can of study team members and quantitative ecologists in be unoccupied over any 6-year period (see July 2011. “Occupancy of Bear Management Units by Although the method had promise, it was Females with Young”). complex and depended on the assumption that the true • Monitoring all sources of mortality for density of female grizzly bears with COY within the independent (≥2 years old) females and males ecosystem is known, information which we currently within the entire GYE. Mortality limits are set lack. Population estimates varied considerably at ≤9% for independent females and ≤15% for based on a range of inputs for the underlying density independent males from all causes. Mortality and workshop participants concluded they could limits for dependent young are ≤9% for known not support this approach at this time. The group and probable human-caused mortalities (see considered an alternative approach based on a mark- “Estimating Sustainability of Annual Grizzly recapture population estimate using sightings of radio- Bear Mortalities”). collared females with COY. The group endorsed this approach in large part because it has the potential to During 2011, demographic monitoring results produce an unbiased estimate for the annual number of triggered a Demographic Review, which entailed a females with COY in the GYE. Work on this method reanalysis of survival and fecundity for grizzly bear in continued through 2011 and final results are expected the GYE using data obtained during 2002–2011. The at the end of 2012. finding triggering the review provided evidence of a The grizzly bear was removed from protection change in trajectory of annual estimates of females under the Endangered Species Act on 30 April 2007 with COY (USFWS 2007b:page 8, number 19; also (U.S. Fish and Wildlife Service [USFWS] 2007a) but see “Assessing Trend and Estimating Population relisted by a District Court order in 2009. During Size Using Counts of Unduplicated Females” in November 2011, the U.S Court of Appeals for the this report). The Demographic