Data from the Wetland Bird Survey have contributed to new research showing how Europe's winter population of Smew has redistributed north-eastwards due to milder winter conditions in the last 25 years. The study, involving scientists in 16 countries, also demonstrated that population growth has been twice as fast inside protected areas compared to outside. Many bird species are showing distributional change in response to global warming. New research using data collected by volunteers taking part in the Wetland Bird Survey shows that Europe's winter population of Smew has redistributed north-eastwards due to milder winter conditions in the last 25 years. In the UK, a small population of typically less than 200 Smew (and in mild winters just a few dozen birds) can be found in winter at favoured gravel pits and reservoirs in lowland England. This UK population has approximately halved since the late 1990s. This study, compiled by scientists in 16 countries (including BTO staff) shows that Special Protection Areas (SPAs) scheduled under the EU Birds Directive, facilitate such distribution change across a species’ entire range. Currently, one third of the total population winters in north-eastern Europe, compared to 6% two decades ago. Furthermore, population growth rate in this region was also twice as fast inside EU Birds Directive’s SPAs compared to those outside over the last 25 years. Thus, well designed protected area networks can mitigate the effects of climate change on biodiversity by safeguarding high quality habitat as species adopt new distributions. These findings confirm that the existence of Special Protection Areas assists species to cope with climate change. However, the results also highlighted severe gaps in the EU Special protection Area network, especially in northern parts of the wintering range. Many countries designated their SPAs more than 20 years ago, when no account was taken of the rapid environmental changes now occurring. More than eight out of ten Smew wintering in Latvia and Sweden do so in currently unprotected areas, and in Finland nearly all individuals winter outside the SPA network. Despite this range shift, it is still important to maintain the network at the southern end of the birds’ range, so that they have somewhere to retreat during particularly harsh winters. Studies such as this can help policy makers review protected area networks to ensure they keep pace with the conservation needs of Smew and other species.

The BTO/RSPB/JNCC Breeding Bird Survey is the primary source of information about changes in national populations of over 100 bird species. Here we describe analyses of this dataset which has identified important spatial variation in population indicators, highlighting previously unreported declines in habitat specialists in southern and eastern Britain. Using biodiversity indicators In the UK, wild bird population indicators are produced annually on behalf of the Government to monitor the health of the environment. These multi-species indices are calculated by averaging the population indices of birds that typically breed in the habitats of interest. The farmland and woodland bird indicators are those that show the largest declines with losses of 54% and 20% respectively compared to the 1970s baseline. However, these figures mask significant regional and local variation. The BTO has used existing land-cover data to develop a new approach to model breeding densities of birds across the UK from BBS surveys for each species in the indicator for two time-periods (1994-96 and 2007-09). These maps were then combined for each indicator set to show fine-scale spatial variation in temporal trends of both multi-species indicators. Declines greatest in the south-east Farmland birds were found to be doing better in western areas where they have been mostly stable compared to eastern areas where they declined extensively since the mid-1990s. Declines were greatest in south-east England and were driven by losses of more than 50% in farmland specialists such as Linnet, Skylark, Starling and Yellowhammer which are Red Listed species in the UK. In contrast to the east-west pattern seen in farmland birds, the woodland bird indicator showed a north-south gradient, with populations in the south faring worse than those in the north. Again, the largest declines occurred in south-east England, particularly for Willow Warbler, Garden Warbler and Bullfinch, where losses of specialists averaged more than 25%, whilst populations generally increased significantly in Scotland. For both farmland and woodland bird communities, indicator trends for specialist species were much more negative than those for generalist species which tend to occupy a wider range of habitats, and showed positive population trends. What are the reasons for these spatial patterns? The fact that both farmland and woodland indicator trends are most negative in the south-east of England shows that bird populations in this region are under significant and previously unrecorded pressure. Compared to other regions, south-east England has experienced the greatest degree of long-term agricultural intensification, fragmentation of natural habitats and urban expansion. While these factors are very likely to have continuing negative effects, rising temperatures and risk of drought may also play a role and further work is required to properly attribute these spatial patterns to specific drivers. The UK Government is committed to national and international policies to reduce threats to biodiversity and the results of this research are important to help policy makers identify the areas where conservation actions should be prioritised.