Validating mammal monitoring methods and assessing the performance of volunteers in wildlife conservation—“Sed quis custodiet ipsos custodies ?”

Many conservation organisations rely heavily on volunteers, and the government often relies on them to achieve tasks for which funding is insufficient—for example, the monitoring of trends in biodiversity on a national scale. Thus, it is critical to deploy non-professionals effectively. In this study we validated and calibrated the data collected by 155 volunteers, assisting with mammal monitoring at Wytham Woods, Oxfordshire, between April 2000 and December 2001. Tasks included small mammal trapping and handling, surveying and censusing for badgers, estimating deer population sizes from dropping counts, and transect surveys for mammal field signs. We analysed the effects of age, gender, previous experience, physical fitness and aptitude on volunteer performance using quantitative measures and qualitative scores. We found that (1) techniques that could be taught to volunteers without lengthy or specialist training were sufficiently accurate to yield reliable data, (2) with approximately half a day of training in each task, volunteers could produce reliable data, verified by professionals, and (3) volunteer teams brought considerable time savings to many tasks, compared with a single professional researcher. Our analyses show that physical fitness was a significant predictor of a volunteer's ability to perform tasks well and, in our particular sample, a male-bias in volunteer aptitude was apparent in some tasks. Previous experience as a conservation volunteer did not enhance performance over that of novices nor did age have any effect on volunteers’ ability. The overall veracity of volunteer data compared well with data collected using more specialist methods or collected by professional researchers using the same method. Volunteers required more time per task and, while they showed a tendency to underestimate population sizes, their results were consistent. Additionally, the programme helped to raise the environmental awareness of volunteers and their understanding of woodland ecology.