Science: Hares today, none tomorrow?: A new survey shows that the once common hare is vanishing from British fields. Angela Wilkes finds them cornered but still kicking

A CASUAL rambler, catching sight of the occasional hare zig-zagging across a ploughed field, might think the animal is as abundant and unthreatened as its cousin the rabbit. After all, hares are still hunted, legally and illegally. They continue to be shot as game, and as farmland pests that damage crops and young trees.

Yet a new national survey funded by the Joint Nature Conservation Committee is expected to confirm later this year that hare numbers have been steadily dropping over the past 40 years. They may now, for the first time, be below the million mark.

The survey - the first ever properly conducted hare headcount - provides the most accurate tally so far. Hundreds of volunteers were involved, from land managers and pensioners to schoolchildren and keen amateur naturalists. They walked over designated one-kilometre squares of countryside and recorded the number of hares they spotted. A computer calculated the likely density of the hare population in any given area from these sightings.

Britain's hare population isn't just in decline; it's also patchy. Numbers are unevenly distributed, with a bias towards the east of the country. 'There have been zero sightings in parts of the west and south west,' says zoologist Mike Hutchings of Bristol University, 'and we assume that here the hare has died out.'

Yet it was the hare, not the rabbit, which was once a folklore fertility symbol. So what has gone wrong in recent years? Theories range from intensified use of herbicides, pesticides and silage cutting, to habitat interference, oilseed rape planting and 'new' diseases. There are also deaths from road accidents, farm machinery, poaching and hunting.

Of these, habitat interference and new diseases seem the most likely explanations. There have been dramatic changes in Britain's arable landscape since the 1960s, and scientists have identified two apparently new hare diseases. Researchers are therefore focusing their attention on these two areas in particular.

The brown, or European hare (Lepus europaeus) evolved on the wild grasslands of central Asia and spread wherever man cut down forests and planted grain. Early English farms, with their patchwork-quilt fields of varied crops, seasonally rotated, suited the hare's feeding habits. It could move around all year to graze on the tender, protein-rich tips of grasses and cereal crops like wheat, to which its digestive system was suited. When these lengthened and hardened into stalks, the animal simply moved on to newer pastures. The hare also needs crops it can hide in: vegetation must be tall enough to conceal it as it crouches motionless by day its in 'form' - a hollow scooped out of the earth.

For hundreds of years there were enough crops planted by man, and at the right time of year, to sustain Lepus europaeus. Then, around the 1970s, the picture began to change dramatically. Populations on previously hare-rich estates plummeted. 'What was it that happened around that time?' asks Dr Stephen Tapper, director for research at the Game Conservancy and an expert on hares. 'The drop coincides with that period, from the Sixties onwards, when arable farmers were modernising everything. They changed from traditional rotation - cereals followed by grass - and abandoned the sowing of winter wheats (planted in October, coming up in February) in favour of spring cereals (planted in February-March, appearing late spring). Instead of nutritious, all-year-round food, hares faced a new cycle of feast in the mild weather and famine in the coldest parts of the year.'

Worst of all, instead of fields of rotated crops, farmers were embracing the monoculture - turning over 10 fields at a time to the same crop. This prairie was useful to the hare for a limited season only, while the growing cereal tips were rich in protein and low in indigestible fibre.

New research by animal ecologist Graeme McLaren at Bristol University is pinpointing changes in habitat that are putting hare populations under stress. He has collected summer crops as well as wild grasses to check their nutritional content and assess their effect on breeding. 'There appear to be fewer leverets born in the peak breeding period, April to July, than there were during earlier studies in the 1970s,' he says. 'If there are food problems, the young suffer first.'

McLaren will also be combing historical records to see if there is a connection between gamekeepers' shooting figures for hares, and changes in the landscape. It is one of the continuing mysteries of the hare's decline that they are sparse in areas such as Devon and Cornwall, despite the fact that old-fashioned farming methods and traditional field layouts are retained there.

But how could modern farming practices tie in with the incidence of apparently new illnesses? Katherine Whitwell, a Suffolk-based veterinary pathologist, is carrying out a unique study of 100 hares that have died of natural causes. Midway through her research, she says, the commonest hare diseases still appear to be the well-known ones - including a common intestinal organism that can go into overdrive, damaging the hare's gut and stopping it absorbing food.

In the mid-1980s, a new viral hepatitis arrived here, apparently from Germany, with devastating results. Known as European Brown Hare Syndrome, it attacks the liver and central nervous system.

There is another new disease that Katherine Whitwell is looking out for among her sample corpses. Though its effects can be monitored - it damages the part of the animal's nervous system that controls involuntary body functions such as digestion - its origins are unknown. It could be due to a bacterium, a fungus or a neurotoxin, directly or indirectly derived from herbage or soil.

Even if the landscape is turning hostile to the brown hare, at least farmers appear to be on on its side. Tales abound of landowners and managers who enjoy seeing hares, and who won't shoot them unless crop damage is getting out of hand. But there are exceptions. Some landlords apparently instruct their keepers to take rifle, silencer and searchlight and exterminate the entire local population overnight.

They do so,reluctantly, in an attempt to deter the heavy-gambling 'four-wheel-drive brigade' - travelling gangs of men in search of hares upon which to set their rival lurchers (cross-bred greyhounds). 'Gamekeepers are threatened and assaulted, police and farm vehicles are rammed and valuable crops get damaged,' say the Essex police, whose Operation Tortoise successfully shifted the problem north and west to other county boundaries.

There is, however, one very modern aspect of farming which could benefit the beleaguered hare - set-aside, where farmers are paid a subsidy to leave land fallow. Provided such havens are allowed to grow rich in weeds and wild grasses, and left undisturbed, there is a chance they might begin to boost Britain's remaining hare population.

HARE FACTS

Boxing pairs of March hares were once thought to be male rivals. Now mammalogists think one of them is a female, repelling advances from the smaller and lighter male.

Leverets are born fully furred and open-eyed after six weeks' gestation. Each is hidden in a separate 'form' or hollow, moving only to suckle twice a day.

Hares can reach 12 years of age, but the lifespan of a British farmland hare is more like 3-4 years.

Hares stand and flash their white belly hair at foxes to let them know they have seen them, saving both the energy required for a chase.

Top hare speeds of 46mph (72 kmph) make it half as fast again as a fox. Zig-zagging, as well as speed, helps it shake off a pursuer.

There are 27 hare species, including the US 'jackrabbit'.

If you find a hare that appears to have died of natural causes, help Katherine Whitwell by telephoning the Hareline: 0860 575655 or 0638 750189.

(Photograph omitted)