Cooperative Fish and Wildlife Research Units Program: all
Education, Research and Technical Assistance for Managing Our Natural Resources

In cooperatively breeding carnivores, the composition (i.e., the number of different sex and age classes) and size of a group influence recruitment and group survival. For group living canids like gray wolves (Canis lupus), breeders are vital to perpetuating the group, and the death or removal of an individual breeder can greatly affect a group’s composition, genetic content, and short-term population growth (Ausband et al. 2015; Ausband et al. 2017). Monitoring these parameters in remote populations through traditional approaches such as radio-telemetry and direct observation is difficult and costly due to geographic obstacles, large home ranges, and reduced sampling opportunities for cryptic and elusive species. Understanding how many breeders are harvested from a population may better our understanding of how mortality can affect groups of cooperative breeders like gray wolves that are exposed to annual harvest; and may be useful for altering management and conservation actions. We estimated the frequency of breeders in harvest and whether breeders were more vulnerable to harvest during the breeding season. We demonstrate a novel approach for using genetic data collected opportunistically from harvested wolves to determine if/when breeders are more vulnerable to harvest and to estimate the minimum number of breeders harvested annually in Idaho, USA, using pedigree analyses. We genotyped and aged 229 adult wolves and 203 pups using tissue and tooth samples, respectively, from wolves harvested between 2014 and 2016. We identified a minimum count of 36 breeders (n = 18 in 2014 and 18 in 2015) and found that breeders were disproportionately harvested (P = 0.08) during the breeding season (January; 25% of all breeders harvested during 2014 and 2015 harvest seasons). We estimate that a minimum of 16% of adult wolves harvested annually are breeders, or roughly 1 in 6. Our estimate of the number of breeders harvested annually is conservative because the pedigree analysis is dependent on both a pup and breeder from the same group having been harvested in the same year, and samples were excluded from the analysis if they were missing age and harvest month data or had <16 confirmed loci. Our results demonstrate that breeders are routinely harvested and that their behavior during breeding season may increase their vulnerability to harvest.