A STUDY OF DUNG DECAY AND PLOT SIZE FOR SURVEYING FERAL PIGS USING DUNG COUNTS

The effects of dung decay and plot size on counts of dung pellets of f eral pigs (Sus scrofa) were investigated in south-eastern Australia. G reater understanding of both could potentially improve survey accuracy and field interpretation of dung counts by managers. Dung pellets per sisted for up to 16 months, with over 50% disappearance within 2-5 mon ths, depending on season. The long persistence suggests the need for c aution in infering recent presence of feral pigs from the presence of intact pig dung. Partial correlation analysis showed the survival rate of pellets during the first month to be significantly negatively corr elated with measures of temperature and rainfall in the month. There w as a significant (P < 0.005) interaction of plot size, over the range 5-20 m(2), and month on the average number of pellets per square metre per month, and a significant (P < 0.01) effect of year on average cou nts. The largest plot size always detected at least one dung pellet bu t smaller plots did not.