title: Detecting grizzly bear use of ungulate carcasses using global positioning system telemetry and activity data.
abstract: Global positioning system (GPS) wildlife collars have revolutionized wildlife research. Studies of predation by free-ranging carnivores have particularly benefited from the application of location clustering algorithms to determine when and where predation events occur. These studies have changed our understanding of large carnivore behavior, but the gains have concentrated on obligate carnivores. Facultative carnivores, such as grizzly/brown bears (Ursus arctos), exhibit a variety of behaviors that can lead to the formation of GPS clusters. We combined clustering techniques with field site investigations of grizzly bear GPS locations (n = 732 site investigations; 2004-2011) to produce 174 GPS clusters where documented behavior was partitioned into five classes (large-biomass carcass, small-biomass carcass, old carcass, non-carcass activity, and resting). We used multinomial logistic regression to predict the probability of clusters belonging to each class. Two cross-validation methods-leaving out individual clusters, or leaving out individual bears-showed that correct prediction of bear visitation to large-biomass carcasses was 78-88 %, whereas the false-positive rate was 18-24 %. As a case study, we applied our predictive model to a GPS data set of 266 bear-years in the Greater Yellowstone Ecosystem (2002-2011) and examined trends in carcass visitation during fall hyperphagia (September-October). We identified 1997 spatial GPS clusters, of which 347 were predicted to be large-biomass carcasses. We used the clustered data to develop a carcass visitation index, which varied annually, but more than doubled during the study period. Our study demonstrates the effectiveness and utility of identifying GPS clusters associated with carcass visitation by a facultative carnivore.
authors.affiliation: College of Forestry and Conservation, University of Montana, University Hall, Room 309, Missoula, MT, 59812, USA. mebinger@usgs.gov.|Interagency Grizzly Bear Study Team, Northern Rocky Mountain Science Center, US Geological Survey, 2327 University Way, Suite 2, Bozeman, MT, 59715, USA. mebinger@usgs.gov.|Department of Ecology, Montana State University, P.O. Box 173460, Bozeman, MT, 59717, USA. mebinger@usgs.gov.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Ebinger
authors.affiliation: Interagency Grizzly Bear Study Team, Northern Rocky Mountain Science Center, US Geological Survey, 2327 University Way, Suite 2, Bozeman, MT, 59715, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Haroldson
authors.affiliation: Interagency Grizzly Bear Study Team, Northern Rocky Mountain Science Center, US Geological Survey, 2327 University Way, Suite 2, Bozeman, MT, 59715, USA.
authors.forename: Frank T
authors.initials: FT
authors.lastname: van Manen
authors.affiliation: College of Forestry and Conservation, University of Montana, University Hall, Room 309, Missoula, MT, 59812, USA.|Montana Fish, Wildlife and Parks, 490 N. Meridian Road, Kalispell, MT, 59901, USA.
authors.forename: Cecily M
authors.initials: CM
authors.lastname: Costello
authors.affiliation: Large Carnivore Section, Wyoming Game and Fish Department, 260 Buena Vista, Lander, WY, 82520, USA.
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Bjornlie
authors.affiliation: Large Carnivore Section, Wyoming Game and Fish Department, 260 Buena Vista, Lander, WY, 82520, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Thompson
authors.affiliation: Bear Management Office, Yellowstone Center for Resources, Yellowstone National Park, P.O. Box 168, Yellowstone National Park, WY, 82190, USA.
authors.forename: Kerry A
authors.initials: KA
authors.lastname: Gunther
authors.affiliation: College of Forestry and Conservation, University of Montana, University Hall, Room 309, Missoula, MT, 59812, USA.|School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, WA, 99164-4236, USA.
authors.forename: Jennifer K
authors.initials: JK
authors.lastname: Fortin
authors.affiliation: School of Biological Sciences, Washington State University, P.O. Box 644236, Pullman, WA, 99164-4236, USA.|Grizzly Bear Recovery Program, US Fish and Wildlife Service, 385 Fish Hatchery Road, Libby, MT, 59923, USA.
authors.forename: Justin E
authors.initials: JE
authors.lastname: Teisberg
authors.affiliation: Interagency Grizzly Bear Study Team, Northern Rocky Mountain Science Center, US Geological Survey, 2327 University Way, Suite 2, Bozeman, MT, 59715, USA.|Shoshone National Forest, US Forest Service, Wapiti Ranger District, 203A Yellowstone Avenue, Cody, WY, 82414, USA.
authors.forename: Shannon R
authors.initials: SR
authors.lastname: Pils
authors.affiliation: National Park Service, Yellowstone Center for Resources, Yellowstone National Park, P.O. Box 168, Yellowstone National Park, WY, 82190, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: White
authors.affiliation: Grand Teton National Park, P.O. Box 170, Moose, WY, 83012, USA.|Grand Teton National Park Foundation, P.O. Box 249, Moose, WY, 83012, USA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Cain
authors.affiliation: Interagency Grizzly Bear Study Team, Northern Rocky Mountain Science Center, US Geological Survey, 2327 University Way, Suite 2, Bozeman, MT, 59715, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Cross
mesh_terms: D000818:Animals; D017753:Ecosystem; D040362:Geographic Information Systems; D011235:Predatory Behavior; D013686:Telemetry; D001503:Ursidae
keywords: Carcass visitation; GPS  Cluster; Multinomial model; Prediction; Ursus arctos