27/04/2015 08:12 BST | Updated 24/06/2015 06:59 BST

Foxycology: Separating Fox Fact and Fiction

Foxes divide opinion more deeply than any other native British mammal. Some see them as beautiful, adaptable animals who provide a connection to the fast disappearing natural world. Others - generally those who kill foxes for pleasure or profit - claim they are pests whose numbers need to controlled.

The demonisation of animals in this way is a deliberate tactic used widely by people who enjoy killing animals. By convincing society that certain species are pests and need to be controlled, unacceptable activities such as hunting, snaring and shooting become accepted as necessary evils.

We know the demonisation of foxes is a deliberate tactic because the most common claims made about foxes are not supported by evidence. For example, in recent debates around the ten year anniversary of the Hunting Act, the pro-hunting lobby repeatedly claimed that fox numbers in Britain have increased since the Act made chasing and killing foxes with packs of dogs illegal. Yet long term monitoring of fox populations by conservation charities shows otherwise.

An 18 year study by the British Trust for Ornithology showed that fox numbers in Britain dropped by 18% between 1995 and 2012, leading scientists to conclude 'the data provides no evidence that fox numbers have increased since the ban'.

Similarly, ten years of data collected by the People's Trust for Endangered Species led them to conclude the proportion of sites recording foxes has stayed more or less the same 'going against claims in the media that we are increasingly overrun by foxes.'

In addition to being too prolific, foxes are also charged with killing large numbers of lambs and destroying famers' livelihoods. Of course foxes do kill lambs, but they are also easy scapegoats, being blamed for killing lambs that actually died of exposure and illness and were subsequently scavenged by a fox.

Multiple studies have shown that predation accounts for roughly 5% of lamb losses, while 95% are due to farm husbandry practices. The percentage of losses that can be directly attributed to fox predation is even lower; less than 1% according a study tracking the fate of 4000 lambs on Scottish hill farms. What's more, the total revenue lost due to this predation equated to only £112 - £298 per farm in any one year. Hardly a devastating impact.

Even if foxes were taking lambs by the dozen, killing them would not solve the problem. Numerous studies have shown that culling foxes by hunting, shooting or any other means does not control their numbers. In fact, in most studies the number of foxes declines slightly when the killing stops.

This makes perfect sense when you understand fox ecology. They are territorial animals and studies show that when a fox is killed a new one moves in quickly, generally within 3 to 4 days. Sometimes several move in to fight over the new territory.

So killing foxes alters the demographics of a population but not its size, resulting in a high turnover of young individuals rather than an established population of longer-lived animals. For most farmers this means it is more cost-effective to simply tolerate predation losses or spend money on improved housing and husbandry rather than culling. And for many the presence of foxes is actually beneficial as they eat their way through millions of rabbits and rats every year.

The lesson from all this is to take claims about foxes, and all wild animals, with a healthy dose of scepticism. Decisions of life or death should be based on evidence, not allegations.