PRELIMINARY FIELD ASSESSMENT OF A CABERGOLINE BAITING CAMPAIGN FOR REPRODUCTIVE CONTROL OF THE RED FOX (VULPES-VULPES)

The use of poison baiting to control foxes is impractical in urban are as and some wildlife reserves because of hazards to non-target animals . More acceptable methods of fox control in such environments are need ed. Cabergoline is a dopamine agonist that has previously been demonst rated to have an abortifacient effect in cats (Felis catus) and dogs ( Canis familiaris). The prolactin-inhibiting action of cabergoline may also result in cessation of lactation. Cabergoline has been shown to b e completely palatable to foxes and is easily incorporated into a non- poisonous bait. The ability of bait-delivered cabergoline to effect th e birth of viable fox cubs was tested in urban Melbourne and rural Ben digo. A sample of 51 natal dens were chosen for this study on the basi s that they had been active for three consecutive years. Thirty treatm ent dens were randomly selected and each treated once during August an d again during September 1994 with eight nonpoisonous Foxoff baits con taining 170 mu g of cabergoline and 200 mg of tetracycline to act as a biomarker. The remaining 21 dens were used as controls. Baits were ra ndomly placed by burial within a 50-m radius of the den. Activity of a ll dens was assessed until December 1994 for direct/indirect signs of fox cubs. Bait uptake was greater than 88% overall for the treatment d ens. The resulting incidence of cubs was significantly lower in the tr eatment dens than in the controls. The potential for cabergoline to be used in urban areas and island populations as an adjunct to conventio nal control methods is discussed.