In 2005 I undertook my very first field study assessing whether a one-off control program could reduce red fox density on an agricultural property in NSW. Despite my efforts of removing 47 foxes in 12 nights, the control program only reduced the fox population by 1 fox per square kilometre. This was my first introduction to the difficulties of managing invasive species and it provided my first lesson on how not to control foxes! The work is now finally published and hopefully the paper demonstrates that isolated and uncoordinated efforts to control foxes are not effective at reducing fox density. Below is a copy of the abstract. Click HERE for a link to the paper.
As a side note, an additional component of the project involved radio-tracking foxes that I had caught and released with VHF collars. Back in those days GPS collars were not available. I spent many late nights tracking the foxes and I thought a few people might appreciate the picture below of the Toyota Landcruiser I modified to allow for radio-tracking via a large antennae that was installed in the tray.
Abstract: Uncoordinated and isolated control programs are often used by land managers, property owners and recreational hunters to control numbers and reduce the impacts of European red foxes (Vulpes vulpes). However, decades of such attempts to eradicate this significant agricultural and biodiversity pest in many countries have failed. We investigated the effectiveness of an uncoordinated and isolated shooting program to determine if it caused any change in red fox population density. We also determined whether shooting is more cost effective than poison baiting for fox control. First, we estimated the density of foxes on an agricultural study property using distance sampling and rates of bait uptake before and after a control program. Second, we estimated the costs associated with undertaking the control program and compared it to the estimated costs of undertaking poison baiting. Prior to control, we estimated a density of 4.18 foxes per square kilometre. After the control exercise, which removed 47 individuals in 12 nights, we estimated a density of 3.26 foxes per square kilometre. Our results provide evidence that one-off control programs are not effective in greatly reducing red fox density, even if the control effort is intensive. Where large-scale control programs cannot be coordinated, isolated programs should therefore involve follow-up campaigns to reduce population recovery. On a local scale, combinations of shooting and baiting may also provide maximum control impact at minimal cost.