The sight of brown hares "boxing" is one of the most arresting spectacles of the countryside, and if you're lucky and you look hard, you can see it now in the arable fields of lowland Britain.
But the behaviour that gave rise to the legend of "mad March hares" is likely to become a less common sight in future, conservationists believe, because of a change in European Union rules about how farms are managed. They fear the animals may start to decline after the abolition of a Brussels scheme from which hares and other farmland wildlife have benefited greatly.
The set-aside system, under which farmers were paid to leave some of their land uncultivated, dates back 20 years to the days of the European "grain mountain" and "wine lake", when payments under the Common Agricultural Policy (CAP) were resulting in massive overproduction of a range of foodstuffs. The policy, an attempt to curb overproduction, while maintaining farmers' incomes, resulted in between 5 and 10 per cent of land remaining unused in a given year.
But while critics of the CAP said paying farmers to do nothing was nonsensical, it had an unanticipated but major benefit: the uncultivated, scruffy, weed-rich fields which resulted provided a haven for animals, birds, plants and insects whose populations had been devastated by intensive agriculture.
Brown hares were major beneficiaries, along with declining farmland birds such as the skylark, the linnet and the corn bunting. After the general introduction of set-asides in 1992 it is estimated that the British hare population, which had declined by 75 per cent since the 1960s, bounced back and rose from about 800,000 to well over a million.
However, the CAP has now been reformed and overproduction is a thing of the past. Furthermore, a massive shift is taking place in the world grain market. In the United States huge amounts of grain are being switched from foodstuffs into biofuels, which, as America is the world's largest grain exporter, means that supply is struggling to meet a growing demand.
The price of wheat and other cereals has more than trebled in the last three years, making farmers keen to use every inch of arable land to grow crops. This has resulted in the European Commission ending set-aside, and from this year, farmers across the EU, including in Britain, are no longer being paid for taking land out of production.
The extent of set-aside was considerable – about 8 per cent of the arable land of Britain. That was an awful lot of scruffy, weedy sanctuary for our wildlife. Now it has gone.
The Game & Wildlife Conservation Trust fears this means that the future for brown hares is now in the balance. "There is little doubt that set-aside has benefited brown hares, and we suspect that numbers of farmland birds and mammals which had stabilised or increased over the last decade, including hares, could now begin to fall again," said Dr Stephen Tapper, the trust's director of policy and public affairs. "We will be monitoring the situation closely."
Brown hares were once a common sight on farmland and their decline with intensive farming was so great that they were one of the first species to be given special conservation status under a governmental biodiversity action plan to bring their numbers up to 2 million by 2010. It is a target that now seems unlikely to be reached.
The trust, which is a lead partner in the biodiversity action plan, along with the Mammal Society, has produced a practical guide for farmers and land managers entitled "Conserving the brown hare". Now it is joining other conservation bodies in calling on the Government to widen farmers' environmental stewardship grant schemes, so that new measures to help the hare can be introduced.
"It would be a sad day if the spectacle of boxing hares became a thing of the past," said Callum Rankine, the Mammal Society's chief executive.
Hare boxing is not two males fighting over a female, as is often assumed, it is a female who is about to come into heat repelling the premature advances of a male.