DISPERSAL OF JUVENILE BRUSHTAIL POSSUMS, TRICHOSURUS-VULPECULA, AFTERA CONTROL OPERATION

Long-distance movements of juvenile brushtail possums (Trichosurus vul pecula) from three habitats on farmland in Hawke's Bay, New Zealand, w ere studied by radio-tracking after a poisoning operation. In the five years after the possum population on the study site had been reduced by 90%, the population recovered to about half its initial density. Du ring that time, about 25% of radio-tagged juveniles dispersed 2 km or more, a maximum of 12.8 km from their natal area, with no significantl y preferred direction. A greater proportion of males dispersed than fe males. All but one of the juveniles dispersing did so before they were one year old, and most made several moves before settling. The bimoda l timing of dispersal in summer and late winter-early spring reflected an underlying similar pattern of breeding. A higher proportion of pos sums dispersed from the low-density pastoral and cropping habitat than from the higher-density habitats of swamp and willows. The dispersal behaviour of juveniles after the control operation differed little fro m that before, suggesting that dispersal of possums is not strongly in fluenced by density-dependent factors at the natal site.