Thomas, Matthew C. C.2010-11-261997https://hdl.handle.net/10182/2873The impact of rabbit (Oryctolagus cuniculus, Linnaeus 1758) control using sodium monofluoroacetate (1080) on possum (Trichosurus vulpecula, Kerr 1792) populations was evaluated at Foxdown Station, North Canterbury. The impact of a planned rabbit control operation on possum abundance, and the level of 'bait-shyness' among possums that survived the poisoning, were both assessed. In June 1996 a 365 ha area was poisoned for rabbits using 1080 carrot baits (0.02%, wt:wt) spread by fixed-wing aircraft. Possum trap-lines were set in the poison area and in an adjacent non-treatment area before and after the poison operation. Percentage kill of the possum population was estimated from changes in trap-catch indices over time and survival of radio-collared possums. Possum bait-shyness was then assessed by comparing bait consumption at paired carrot and maize bait stations and by direct observations of behaviour of possums feeding on carrot and cereal baits. Possums were present in significant numbers in both study areas. Rabbit poisoning killed an estimated 12-37% of possums in the treated area. Large possums were significantly more likely to survive rabbit poisoning than were lighter individuals, indicating that rabbit poisoning may be selecting for increased possum body size. As predicted, at least 50% of the possums that survived rabbit poisoning were found to be 'shy' when subsequently exposed to 1080 bait. Shy possums were unable to discriminate between toxic and non-toxic carrot baits; a combination of the carrier (carrot base) and Bayer V200 green dye appeared to be the cues used to avoid such bait. The implications of this bait-shyness, and the potential for the simultaneous control of rabbits and possums in farmland areas where both species pose a threat to agricultural systems, are discussed.enpossumTrichosurus vulpecularabbitsOryctolagus cuniculuspoison1080aversionshynessbait stationssodium monofluoroacetateThesisDigital thesis can be viewed by current staff and students of Lincoln University only. If you are the author of this item, please contact us if you wish to discuss making the full text publicly available.Q112854467