Scientists from the Royal Society for the Protection of Birds and the British Trust for Ornithology have found that intensive grazing practices can have a major impact on bird species.
New clues are emerging about the reasons for a massive decline in farmland bird species whose song used to be such a part of the sound of the British countryside.
Recent surveys have shown that the number of skylarks, grey partridge, corn bunting and yellowhammer plummeted in the final quarter of the 20th Century.
Research on the reasons for this decline has so far focussed on the intensive growing of crops with the aid of pesticides and chemical fertilisers.
But it now seems that the way grass is grown to feed livestock could be equally important. And organic farms may be no better for the birds than their conventional counterparts.
Barren fields
Studies being presented to the British Ecological Society this week suggest that changes in UK grasslands have deprived farmland birds of food and shelter.
Scientists from the Royal Society for the Protection of Birds and the British Trust for Ornithology have found that intensive grazing practices can have a major impact on bird species.
For instance, frequent cutting of grass to make silage instead of allowing it to grow into hay makes for barren fields, with no cover for nests or seeds for food.
Early results from an RSPB study of 400 grass fields in Shropshire, Staffordshire and Cheshire suggest that organic practices which avoid the use of chemicals are no better than conventional farming in providing food for birds.
Organic 'no better'
It seems that the problem for skylarks and yellowhammer is intensive livestock farming of any kind, whether or not it follows organic rules.
The research also suggests that dairy farms provide especially poor pickings for birds. It seems the situation has been made worse by the specialisation of farming, with large areas of the West of England, for example, given over almost exclusively to livestock.
Planting just a few crops in amongst the grassland can significantly boost bird populations, the scientists say.
The Soil Association, which regulates Britain's organic farms, says that chemical-free methods benefit wildlife as a whole, including birds, but accepts that the cutting of grass for silage can cause problems for ground-nesting species.
It says it is working with the RSPB and English Nature to develop more bird-friendly practices.