Skylark, lapwing, linnet and grey partridge are all familiar farmland birds whose populations have dropped by more than 50 per cent in the past 25 years alone. And in that time, the tree sparrow has suffered an 89 per cent decline.
Forty per cent of our hedges have disappeared since 1945, 97 per cent of our flower-rich hay meadows have been destroyed, 96 per cent of our peatlands have been lost and thousands of our ponds have vanished.
Seventy-five per cent of Britain is farmed, and changes in agricultural practice have made the average field about as friendly to wildlife as the average car park.
"The biggest single factor behind the decline of Britain's biodiversity has been intensive agriculture," says Dr Simon Lyster, director general of The Wildlife Trusts. "I don't blame farmers for what has happened. I blame the system which has created the vast production subsidies which have effectively forced farmers to farm in the way they do."
"The key challenge now is to create a system whereby farmers who want to farm in a more wildlife-friendly way are not penalised financially. The agri environment programmes in Britain need to be developed and expanded, but the big prize is radical reform of the Common Agricultural Policy so that enhancement of the environment is a central objective of any support system."
For example, says Dr Lyster, a farmer wishing to qualify for subsidies would have to meet certain conditions such as setting aside an agreed percentage of land for wildlife, leaving broad field margins, building "beetle banks" - green areas to attract nature's pest squad - and using less damaging chemicals in field centres.
Since the 1970s, farm subsidies paid under the CAP have given farmers significant financial incentives to continually increase production. In our remote uplands almost 75 per cent of our heather moorlands are at risk of overgrazing by sheep. Overstocking has been encouraged by a system of subsidies paid to hill farmers per head of sheep rather than on a farm acreage basis - an option The Wildlife Trusts prefer. Numbers of ground- nesting birds such as the merlin and golden plover have plummeted.
The Moorland Scheme was introduced in 1994 and pays farmers pounds 30 a head for every ewe they remove in line with stocking targets. Since its introduction, at last count only 15 English and five Welsh farmers had signed up, removing 6,000 ewes. No farmers in Northern Ireland have joined.
"Incentives to de-stock are simply not competitive with livestock subsidies and as a result farmers trying to make a livelihood have not joined," says Dr Simon Lyster.
The Wildlife Trusts demonstrate good practice on their own farms such as Wells Farm, in Oxfordshire - an arable farm which makes a profit and shows how a farm can be commercially viable and wildlife friendly at the same time. The Wildlife Trusts also work closely with hundreds of farmers and land managers, encouraging them to enter into some of the conservation grant schemes. These schemes provide annual payments for farmers willing to draw up a management agreement and care for wildlife sites sympathetically. The Ministry of Agriculture's Countryside Stewardship and Environmentally Sensitive Areas initiative are two programmes favoured by the Trusts.
In Devon, The Wildlife Trust's agricultural liaison officer has persuaded 175 farmers to join Countryside Stewardship and care for the area's unique Culm grassland. The payments range from pounds 70/pounds 100 per hectare per year for retaining ancient meadows to pounds 275 for recreating heathland and pounds 125 for a gate - but access is not a requirement.
The Wildlife Trusts are also influencing policy at home and abroad in Brussels' corridors of power. Dr Simon Lyster is a member of the Agricultural Reform Group which includes farmers and conservationists as members. He believes many farmers would welcome the chance to farm in a more environmentally sensitive way if the financial incentives were right and sees an opportunity in the next round of world trade talks. These, he says, are likely to result in massive pressure from the Americans for Europe to end its production subsidies and to replace them with something greener. The Wildlife Trusts will be pressing hard to bring about this change.