A study that examined 12 wind farms in the UK has suggested that numbers of several types of breeding birds are reduced close to wind turbines.
The study, funded by RSPB Scotland, the Scottish government, Scottish Natural Heritage and the Scottish Mountaineering Trust, claims that if wind farms are sited inappropriately in areas where vulnerable birds breed at high densities, then their populations may subsequently decline.
Wind farms are regarded as having two major impacts on bird populations. The first, collision, has received most attention and has been shown to result in bird-strike mortality, notably of raptors, at some sites. The second, disturbance displacement, which was the subject of the new study, describes the fact that birds may use areas close to the turbines less often than would be expected.
The 12 wind farms were surveyed six times during the breeding season for a dozen common species including waders and gamebirds (golden plover, lapwing, curlew, snipe, red grouse), raptors (buzzard, hen harrier, kestrel), and songbirds (skylark, meadow pipit, stonechat and wheatear).
The distribution of birds across each wind farm was then compared with that on similar nearby sites without turbines. Seven species – buzzard, hen harrier, golden plover, snipe, curlew, wheatear and meadow pipit – were found less often than would be expected close to the turbines, indicating that breeding densities of these species are reduced by 15-53 per cent within 500m of the turbines.
Among these, the hen harrier and golden plover are protected under European law, and the curlew is a high-priority species under the UK Biodiversity Action Plan due to its population decline.
James Pearce-Higgins, a senior conservation scientist with RSPB Scotland, and the study’s lead author, said the results emphasised the need for wind farms to avoid areas with high densities of potentially vulnerable species such as curlews and golden plover.