Journal of Chemical Ecalogy, 1,1ol. 21, No. 9, 1995 RESPONSES OF BEAVER (Castor canadensis KUHL) TO PREDATOR CHEMICALS AXEL ENGELHART l and D. M(0LLER-SCHWARZE* SUNY College of Environmental Science and Forestm, Syracuse, New York 13210 (Received January 6, 1995; accepted April 25, 1995) Abstract--Free-ranging beaver (Castor canadensis) in two different beaver populations in New York State were exposed to predator chemicals to test feeding inhibition. Solvent extracts of feces were applied to stem sections of aspen, the preferred food tree of beavers, permitting smelling and tasting the samples. Predator odors were from wolf (Cants lupus), coyote (Cants latrons), dog (Canis familiaris), black bear (Ursus americanus), river otter (Lutra can- adensis), lynx (LytLr canadensis), and African lion (Panthera leo). The exper- iment was repealed. The predator odors reduced feeding compared to untreated or solvent-treated controls. One population consumed 17.0% of the samples with predator odor and 27.0% of the controls in summer, and 48.4% and 60.0%, respectively, in autumn. The other population accepted 3.15% of the predator odor samples and 11.05% of the controls in summer. Coyote, lynx, and fiver otter odors had the strongest effects. Diesel oil and bitter-tasting neem extract had weaker eflkcts. Predator odors are promising as feeding repellents lbr beaver. Key Words--Adirondacks, Allegany State Park, allopatric, aspen, beaver, Castor canadensis~ feeding inhibition, Populus tremuhffdes, predator odor, repellent, sympatric. INTRODUCTION Populations of the North American beaver (Castor canadensis Kuhl, 1820) are currently increasing because low pelt prices discourage fur trapping. The grow- ing beaver populations cause considerable wildlife damage by flooding roads, forests, and fields and by cutting down valuable trees. This intensifies the need for effective beaver management. Among other means, environmentally corn- *To whom correspondence should be addressed. *Current address: Schulstr. 14, 71296 Heimsheim, Germany. t 349 2751-3028/95/0900 1349507.50/0 ~ 1095 Plenum Publishing Corporation