Consumption of acute and chronic toxins by 1080 bait shy possums in captivity

Abstract

Aversions caused by sub-lethal doses of sodium monofluoroacetate (1080) apparently persist in captive possums for at least 3 months, during which time such possums remain averse (or 'shy') to bait containing either a chronic or acute toxin (Morgan, Meikle & Hickling 1995). This suggests that when shyness has been induced with cereal 1080, such possums cannot be successfully controlled by reapplying cereal bait, regardless of the toxin used. However, when a chronic toxin is used in the field it seems that possums eat progressively more bait at each night's exposure, until eventually the cumulative dose becomes lethal (R. Henderson, unpublished data). These pen and field trials suggest different approaches for how best to combat 1080 shyness. Further trials were therefore required to clarify this issue, by ascertaining how the type of toxin influences the amount of bait that shy possums eat when they next re-encounter cereal bait, and whether nightly per capita consumption increases or decreases during prolonged reexposure to such baits.