U.S. Department of Agriculture: Animal and Plant Health Inspection Service


Date of this Version

March 2001


Published in Wildlife Society Bulletin 2001, 29(1):292-2.96.


Wildlife managers use carcass searches to assess mortality resulting from biological (e.g., diseases) and physical (e.g., structure collisions) sources. Carcass searches may occur over large areas and need to be completed rapidly because of scavenging and decomposition. However, small carcasses are often missed when dense vegetation is searched. We placed carcasses of house sparrows (Passer domesticus) in dense cover of residual and newly grown vegetation and compared searching efficiency of humans and canines. Dogs received no special training in searching for passerine carcasses. In 36 trials conducted in 5 x 40-m plots, human searchers found 45% (SD=19) of the carcasses compared to 92% (SD=13) for dogs (P=0.005). The ratio of recovered to missed carcasses was approximately 12:l for dogs and 1 :I for humans. The improvement in searching efficiency using dogs was similar (P=0.58) between residual cover (searched in April) and new growth cover (searched in August). A greater rate of searching efficiency is obtained per unit of time by using dogs. Greater efficiency improves quantitative and qualitative assessments of avian mortality in the field.