Evaluation of bait stations for broadacre control of rabbits

Abstract

The efficacy of bait stations (200-L drum cut in half longitudinally) for the broadacre control of rabbits was compared with that obtained with standard trail-baiting procedures in the southern agricultural region of Western Australia. Bait stations were tested with and without the provision of pre-feed. The bait used was 1.0% 1080 One-shot oats, and corresponding experimental control sites were treated with unpoisoned oats. On the basis of spotlight counts before and after baiting, the reduction in rabbit numbers obtained with bait stations in the absence of pre-feed was poor, with a mean reduction of only 27% within 14 days. These reductions did not improve appreciably where sites were monitored for a further 28 days (i.e. 42 days in total). In contrast, the provision of pre-feed for 21 days prior to adding the 1080 bait resulted in a mean reduction in rabbit numbers of 57% within 14 days after the poisoned bait was added. However, the greatest reductions in rabbit numbers were achieved with trail baiting, where, relative to pre-treatment counts, rabbit numbers were reduced by 72% at Day 7 and by 84% at Day 14. The oats used to manufacture the 1080 One-shot product are subjected to gamma-sterilisation to prevent the germination of the oats, and any associated seeds of weed species. When offered a choice (matched sets), there was no difference in the amount of non-toxic gamma-sterilised oats and unsterilised oats consumed by free-ranging wild rabbits. On the basis of the costs incurred during the trials, trail baiting was by far the cheapest option for the broadacre control of rabbits. However, the cost of using bait stations would be discounted to some degree once these stations are able to be reused. The cost of trail baiting to protect a 15-ha 'border' of crop was $157 and $113 for three and two parallel trails (6 kg km–1 trail–1), respectively.