23 October 2014 Last updated at 15:39
By Claire Marshall
BBC environment correspondent
Farmland birds are at their lowest levels since records began, according to government figures.
Numbers of birds such as grey partridge, turtle dove and the starling are down more than 85% since 1970s.
The figures come from an assessment of wild bird populations in England, which has been compiled by the Department for Environment and covers 118 different bird species.
It includes data on 19 species reliant on the farmed countryside.
Over the last 40 years, indicators used in the report show a decline in farmland birds of 56%, with turtle doves declining the most rapidly - down 96% since 1970.
Other species under pressure include skylarks - down 62% since 1970 - and lapwings which are down by 50%.
Much of this decline is blamed on the rapid change in farmland management in the late 1970s and early 1990s.
Modern intensive farming methods means that fields have become much bigger, and more chemicals are used. With a significant loss of hedgerows, birds have fewer places to nest.