Use of predator odors as repellents to reduce feeding damage by herbivores

Abstract

The effectiveness of predator odors (fecal and urine) in suppressing feeding damage by black-tailed deer was investigated in pen bioassays at the University of British Columbia Research Forest, Maple Ridge, British Columbia, Canada. A total of eight bioassay trials tested the effects of these odors on deer consumption of salal leaves and coniferous seedlings. Cougar, coyote,and wolf feces as well as coyote, wolf, fox, wolverine, lynx, and bobcat urines provided the most effective suppression of deer feeding damage. Novel odors of ammonia and human urine did not reduce feeding. Predator fecal odor formulations in direct foliar application, adhesive application, and in plastic vials were all effective in suppressing deer feeding. Of all urines tested, coyote provided the most consistent suppression of deer browsing on salal. Deer consumed significantly more untreated Douglas fir and western red cedar seedlings than those protected by coyote urine odor. The active repellent components of predator odors which suppress deer feeding may be suitable for encapsulation in controlled-release devices which could provide long-term protection for forest and agricultural crops.