Predation
Killing foxes and controlling fox density: when are they the same thing? It is not always certain that culling foxes amounts to effective control. © Danny Moore
BACKGROUND Foxes are culled to protect vulnerable prey species from predation on shooting estates and wildlife reserves. It’s a defensible practice if it works. But how many fox control efforts do make a worthwhile impact on fox density? Does replacement of culled foxes through immigration defeat the aim in some situations?
32 | GAME & WILDLIFE REVIEW 2019
Predator-removal experiments like Salisbury Plain and Otterburn have shown that control of predators including foxes can make a substantial difference to prey numbers. In those studies, the predator control clearly was effective. But elsewhere, regional fox population, operator skills and resources, and habitat may all be very different, and it is not certain that culling foxes always amounts to effective control. In particular, if culling takes place on a relatively small area like a shooting estate and fox density in the surrounding region is high, culled foxes may be replaced rapidly through immigration. Does that make it futile? This puzzle applies to virtually all lethal control of predators and pests, so it’s an important question to answer. What we did It is almost impossible to measure fox density in the field where culling is ongoing, because the situation changes so rapidly. Instead, we devised a method of analysis that teases this information from daily records of fox culling activity by gamekeepers. The data we used were recorded in the 1990s by 74 gamekeepers on estates reflecting a wide range of circumstances across Britain. All contributors used night shooting with spotlamp and rifle (‘lamping’) as their preferred culling method and recorded both
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