It is widely recognised that nearly all of the landscape in Britain is man made and it has been suggested ( entirely logically I believe) that the distribution and suite of bird species is equally ‘man made’.
The decline in farmland birds relates to the changes since c 1950 when modernisation and intensification of agriculture began at the government’s behest and surveys of breeding birds started soon after. In the 1700’s prior to the enclosed mixed farming fields that lasted until the mid twentieth century, there were probably species associated with more open landscapes, shrikes and bustards for example.
Whilst hardly a farmland species the discovery of a White tailed eagle talon, thought to be two and a half thousand years old, at North End, Yatton a few years ago gives an indication of the changes in landscape and bird life since then. Species such as Linnet, Yellowhammer and Grey Partridge are likely to have inhabited the ‘wastes’ of medieval England and in earlier times of much more tree cover, woodland species must have been more numerous than today and Skylarks for example less widespread. So the species we know as farmland birds have actually increased in numbers after the enclosures.
It has been calculated that there is a higher biomass of birds on farmland now than fifty years ago. Woodpigeons and Carrion Crows have increased dramatically in recent years and they represent more biomass than huge flocks of finches or buntings. For most of the year Herring, Lesser Black Backed and Black Headed Gulls feed on agricultural land in large flocks.
The hope for our traditional farmland birds locally lies I think in their ability to move into gardens and use feeding stations. In arable areas margins and seed and flower rich plots attract large numbers of nesting and feeding birds. Surely the Goldfinch has cracked the problem, it’s population has risen exponentially since it took to inhabiting suburban and even urban areas and feeding in gardens. There have been a few reports of Linnets using feeding stations and even fewer of Yellowhammers doing likewise but if these and other species became confident to inhabit gardens surely their numbers would increase.
Indices of bird populations have shown that birds that have adapted live alongside humans have fared well and no doubt the same applies to other taxa, look at the numbers of deer now compared with thirty years ago..So please keep wild areas in your garden and refrain from using pesticides or chemicals.