The woylie (Bettongia penicillata) was removed from the endangered list after the Western Shield fox baiting program and translocations led to a recovery in woylie numbers. Recent investigations have suggested that there may be a substantial decline in the abundance of woylies in the South West forests of Western Australia. Although this decline had not yet been statistically verified, indications suggested the decline to be extreme enough that immediate action may need to be taken, including the possible reinstatement of woylies to the endangered species list. A definitive and independent review of the historical trapping data to give an objective statement regarding the decline (or otherwise) of the woylie population was therefore required.
Woylie trapping data in the Upper Warren region had been collected over a number of years for long-term monitoring research (P. Christensen and N. Burrows), the "Kingston Study" into timber harvesting impacts and associated research (A. Wayne), Western Shield monitoring and other Donnelly District activities (I. Wilson). Notably, the data had not been specifically collected for the purposes of Data Analysis Australia's analysis and as such had several impacts on the modelling. In particular, there was a lack of data available for each site, trapping was not performed consistently for the different research projects, there were changes in site boundaries and various individuals completed the data collection and data entry.
In saying this, the data that has been collected is extensive and is the richest source of woylie data available for this analysis.