Wandering mariners: Gannets and offshore renewables
With European member states committed to obtaining 20% of their energy from renewables by 2020, the number of offshore wind, wave and tidal developments is increasing. Seabirds could be affected in many ways, including through loss of foraging habitat, and collision with wind turbines. In a new study by the University of Liverpool, BTO and Alderney Wildlife Trust, GPS tags were deployed to examine how Gannets breeding on Alderney use their marine environment. Gannets visited nine sites earmarked for offshore renewables, suggesting these birds could be affected by development in these areas. These sites fell in three different territorial waters – those of France, the United Kingdom and the Channel Islands – illustrating how the impact of such developments needs to be considered at an international level for highly mobile species. Since tracking technology is becoming cheaper, longer lasting, more accurate and easier to use on a wide range of species, such studies could form an integral part of the environmental impact assessment process for marine renewable developments.
Finch trichomonosis: emergence and spread
Finch trichomonosis has caused epidemic mortality in Greenfinches and Chaffinches across the British Isles since its emergence in 2005. A new study, which uses data from GBW, GBFS and BBS, shows that the British population of breeding Greenfinches has fallen from approximately 4.3 million to 2.8 million birds, and that the number of Greenfinches visiting gardens has also halved during this time. Chaffinches have been less severely affected. The study suggests that trichomonosis might have jumped to finches from Woodpigeons at shared feeding sites. This work has important implications for managing the on-going impact of the finch trichomonosis epidemic, and for assessing the likely effect of any future wildlife disease outbreaks.
Stepping stones to the north
A new study involving BTO has shown how birds, insects and spiders have used nature reserves and areas protected for wildlife to expand northwards in response to climate change and other factors. Using data from volunteer recording and national monitoring (including BTO surveys) from the 1970s onwards, the researchers showed that species disproportionately colonised protected areas in their northward expansion. These sites were approximately four times more likely to be colonised than would be expected given their availability in the wider countryside. Three key vulnerable birds, the Bittern, Woodlark and Dartford Warbler were significantly more likely to be associated with protected areas in newly colonised areas than would be predicted by chance alone. As many species will need to shift their distribution to respond to climate change, this study underlines the vital long-term importance of protected areas in conserving biodiversity.
Quantity and quality: the importance of un-cropped land for farmland birds
European agri-environment schemes provide prescriptions to farmers to sustain wildlife and biodiversity on farmland. Such prescriptions include leaving areas of farmland un-cropped. New work by the BTO, the Game and Wildlife Conservation Trust, Rothamsted Research and NIAB-TAG has investigated the quantity of un-cropped land needed per farm to maintain bird populations. The average area of un-cropped land was found to be significantly associated with the abundance of key declining farmland bird species. Overall, farms in which at least 10% of land area was left un-cropped supported bird populations that were approximately 60% larger than farms with less than 5% un-cropped land. This research demonstrates the imperative need for sufficient habitat quantity and spatial management in European agricultural policy prescriptions, which together with habitat quality, are necessary for stabilising populations of declining farmland birds.
BBS data prove benefits of Environmental Stewardship for birds
Publicly funded agri-environment schemes are widely used in Europe to address biodiversity losses in farmland ecosystems, but evidence of their effectiveness has been limited. New research by the BTO has used BBS data to show that management to enhance winter seed availability for farmland birds in England as part of Environmental Stewardship (ES) has significantly reduced the rate of population decline for several species, including Yellowhammer, Linnet, Reed Bunting and Grey Partridge. The types of management involved (leaving stubble overwinter and planting wild bird seed crops in field margins) were mostly implemented under the “broad and shallow” Entry Level Stewardship (ELS) scheme. In keeping with previous research, measures to enhance breeding habitat had little effect across species. Although significant, the benefits of stubble and wild bird seed were small, and only slowed population declines rather than reversing them.