Effectiveness of Predator Fecal Odors as Black-Tailed Deer Repellents

Abstract

Pen bioassays were conducted to evaluate the effectiveness of predator fecal odors as deer repellents. Aqueous extracts from predator feces were more effective than BGR (4.9% egg solids) and as effective as BGR-P (36% egg solids). In Test I, browsing reductions for the predator feces tested were: bobcat (Felis rufus)-51%; mountain lion (F. concolor)-27%; wolf (Canis lupus)-17%; and coyote (C. latrans)8%. The efficacy of fecal extracts in Test I correlated with the concentration of predator feces in initial formulations (5, 10, and 20% by weight). In Test II, increasing the concentration of feces to 30% for bobcat and mountain lion did not increase their repellency. Fecal odors of predators significantly suppressed the feeding activities of black-tailed deer (Odocoileus hemionus columbianus); however, additional laboratory and fieldwork are needed before predator odors can be used operationally. J. WILDL. MANAGE. 49(2):358-362 Chemical signals of an olfactory nature modify behavioral activities of mammalian prey species (Griffith 1920, Stoddart 1976, Thiessen and Rice 1976, Hennessy and Owings 1978). In some species of ungulates, odors of predators elicit the same response as actual sightings of predators (Schaller 1967). These concepts are employed occasionally when people attempt to protect gardens, orchards, landscaping, and other plantings from animal damage by placing the hides or seats of predators around or near the vegetation (Ives 1960; Miiller-Schwarze 1972; I. Guaditz, pers. commun.). In the Pacific Northwest, browsing damage to forest tree seedlings by deer and elk (Cervus elaphus) can cause seedling mortality or height reduction such that reforestation efforts may fail (Black et al. 1969, Crouch 1974). Several deer repellents are marketed for the control of browsing damage to forest trees and other vegetation, yet there is a continuing interest in the scientific community to develop a more repellent or longer lasting formulation. Other investigators have demonstrated that the presence of predator seats (Miiller-Schwarze 1972) and fecal odors (Campbell and Bullard 1972) in bowls of food offered to black-tailed deer suppress feeding. Miiller-Schwarze found that feces from predators sympatric with blacktailed deer elicited the most consistent negative response and suggested that black-tailed deer and possibly other ungulates possess an innate negative response to predator odors. Additional information on the relationship of predator odors and cervid browsing behavior is needed to determine whether such odors can be used as repellents. As part of a more comprehensive repellent screening program, this investigation evaluated the efficacy of several predator fecal odors as deer-browsing deterrents. We thank D. L. Dunham for statistical support during the bioassay of predator odors. The assistance of D. M. Hancocks and G. W. Jorgensen of the Woodland Park Zool. Gardens and W. J. Iliff and J. S. McCusker of the Washington Park Zoo is appreciated for providing feces from captive animals. J. A. Rochelle, I. Gauditz, and R. J. Anderson provided helpful comments on the manuscript.