England farmland bird number cut in half
The majority of this decline has occurred between the late 1970s and early 1980s largely due to the impact of rapid changes in many farmland management practices during this period.
However the decline has slowed to 8% between 2010 and 2015.The large declines in the abundance of many farmland birds have many known and potential causes.
For a large part, declines have been caused by the changes in farming practices that have taken place since the 1950s and 60s, such as the loss of mixed farming, a move from spring to autumn sowing of arable crops, change in grassland management (e.g. a switch from hay to silage production), increased pesticide and fertiliser use, and the removal of non-cropped features such as hedgerows.
The rate of these changes, which resulted in the loss of suitable nesting and suitable feeding habitats, and a reduction in available food, was greatest during the late 1970s and early 1980s, the period during which many farmland bird populations declined most rapidly.
Some farming practices continue to have negative impacts on bird populations, but most farmers can and do take positive steps to conserve birds on their land.
In particular, a number of incentive schemes encourage improved environmental stewardship in farming, with some measures specifically designed to help stabilise and recover farmland bird populations.
These include the provision of over-wintered stubbles and planted wild bird crop covers to provide seed in the winter, uncropped margins on arable fields and sympathetic management of hedgerows.
Changes in numbers experienced by some species may, to a lesser extent, be further driven by other pressures. For example, there is evidence of an adverse impact from disease for some species, for example greenfinch.
The farmland bird index is comprised of 19 species. The long-term decline of farmland birds in England has been driven mainly by the decline of those species that are restricted to, or highly dependent on, farmland habitats (the specialists).
Between 1970 and 2016, farmland specialists index declined by 73% and farmland generalists declined by only 4%. ■