Startling decline in farmyard birds

However their unique presence could now be under threat after a startling decline in bird populations was revealed, with some species shown to be breeding at less than half the rate they were 40 years ago.

Government figures show that grey partridges, turtle doves, starlings, tree sparrows, yellow wagtails and corn buntings have all declined by more than 70 per cent in number since 1970.

The current populations are now at the lowest levels since records began and mean that in total more than half of Britain's farmland birds have disappeared since 1970.

Woodland bird levels have also dropped by 24 per cent while water and wetland bird levels declined by eight per cent.

Populations of popular woodland species including wood warblers, willow tits, tree pipits and lesser spotted woodpeckers all dwindled during the past 40 years.

Falls were also reported in non-bird populations with many species of butterflies and bats declining during the time frame.

Plant diversity also dropped while the size of fish in the North Sea is also said to have diminished.

The figures were published in a report from Defra, titled Indicators of Biodiversity in England, which looked at how our ecology today compared with that of 1970. They will now provide a baseline for future environmental strategies.

While the study showed that much of the decline occurred during between the late 1970s and early 1990s, there have been marked falls in recent years as well.

Turtle doves, for example, declined by 47 per cent between 2003 and 2008 while reed buntings fell by 22 per cent over the same period.

The study has shown improvements in some areas of the country's natural environment, with seabird levels having risen dramatically in number in recent decades.

Some good news was also revealed in the respect that there were falls in the number of so-called "invasive species" – wildlife non-indigenous to the UK.

Sustainable fishing stocks were said to have improved while hazardous pollution in marine areas has declined. Interest in the natural world, too, seems to be on the increase, with visits to nature reserves having risen since 1970.

However, questions will be raised about the state of Britain's wildlife following the report, with one animal charity calling upon the Government to "tweak" current environmental policy towards helping bird populations recover to previous levels.

Dr Mark Avery, the Royal Society for the Protection of Birds' conservation director, said: "It is staggering that farmland birds, such as the turtle dove and lapwing, have reached such a low ebb.

"But the good news is that we know how to turn around these declines; everyone now needs to play their part and get on with the job," he said.

Dr Avery said that a secure future for farmland wildlife rested with farmers being financially rewarded for managing land in an environmentally-friendly way, through so-called agri-environment schemes. Key among these schemes is the Entry Level Scheme (ELS) which covers 70 per cent of England's farmland, a scheme currently under review by Defra. In broad terms ELS seeks to reward farmers

who dedicate a portion of their land to the promotion of wildlife, usually by leaving sections free of crops to allow nesting areas for birds.

Dr Avery said: "Defra only has to tweak ELS a little to ensure a recovery in farmland birds such as skylarks and corn buntings. Our children could then hear as much bird song as did their grandparents. A countryside richer in birds is within our grasp."

The RSPB linked the decline of farmland birds to what it described as "decades of habitat change resulting in a lack of suitable nesting sites and a shortage of food in spring or winter".

But it said that the reasons and causes driving the decline of woodland birds were less clear, but ongoing research was being conducted to identify the reasons.

However the Defra report said: "The decline of bird species is a complex issue which cannot be attributed to a single factor."

Farmers in England have in the past 18 months established the Campaign for the Farmed Environment to improve biodiversity on UK farms.

The new figures come just a few weeks after Defra said that significant improvement in the quality of Yorkshire's wildlife sites had been made.

As much as 95 per cent of England's finest wildlife and geological sites, covering more than one million hectares of countryside, are now classed as being in favourable state or recovering condition.