Comparison of two methods used to characterize the summer diet of gray wolves (Canis lupus)

• Main Author: Trejo, Bonnie S.
• Other Authors: Golightly, Richard T.
• Format: Master Thesis
• Language: English
• Published: California State Polytechnic University, Humboldt 2012
• Subjects: Wolf summer diet; GPS-telemetry; Scat analysis; Humboldt State University > Theses > Wildlife; Large carnivore diet; Alces alces; Canis lupus; Bison bison bison
• Online Access: http://hdl.handle.net/2148/1031

Fecal (scat) analysis has been used to assess the diet of large carnivores because the method is non-invasive, economical and suitable to the study of elusive animals. Global positioning system (GPS) telemetry has also been used to assess large carnivore diet by locating individuals so as to detect prey carcasses. Here, the summer diet of gray wolves (Canis lupus) in northwestern Wyoming (n = 11 packs) was characterized using scat analysis. The diets of four packs were compared to two time-coinciding GPS-telemetry studies to evaluate differences in estimates of prey frequency and biomass consumed. Scats were collected during the summers of 2003-2009 (n = 1772) and examined for prey remains. Neonate cervid (elk, Cervus elaphus; deer, Odocoileus spp.; and moose, Alces alces) remains occurred in 53% of collected scats but only accounted for approximately 30% of the estimated relative biomass consumed by wolves. Remains of adult elk, adult deer and adult moose occurred in 26%, 14%, and 3% of collected scats, respectively. Combined, adult cervids (elk, deer, moose, and undetermined adult cervids) were estimated to provide 63% of the relative biomass consumed by wolves. Other prey items included: bison (Bison bison), bighorn sheep (Ovis canadensis), beaver (Castor canadensis), small rodents, lagomorphs, and birds; combined, these prey items were estimated to provide 7% of the biomass consumed by wolves in northwestern Wyoming. When cervid prey frequency and biomass were compared between scat analysis and GPS-telemetry the results of scat analysis significantly differed from GPS-telemetry for some prey items. Scat analysis detected a greater number of prey items than GPS-telemetry. Prey items not detected by GPS-telemetry accounted for approximately 6% of the estimated biomass consumed by wolves. The majority of prey items not detected by GPS-telemetry were small-bodied prey such as beaver, small rodents, lagomorphs, and birds. Although, GPS-telemetry failed to detect adult deer in the diets of two packs, and ...