The winter of 2010 was particularly harsh, with temperatures well below average and more days than normal where the ground was frozen. As ground feeders, Skylarks are severely affected by such conditions, which may account for the fall in numbers. BBS population trends are published annually for 60 bird species in Scotland. While a number of species have declined, many birds are thriving in Scotland, including Bullfinch, which increased by 72% between 2010 and 2011. There are indications that Bullfinches are changing their behaviour to take advantage of bird food in gardens, and the Scottish BBS trends show that some other species that make use of gardens are also increasing. These include Great Spotted Woodpecker and Goldfinch, which have increased in Scotland by 312% and 133% respectively since the start of the survey in 1994.
Kate Risely, BBS organiser at the British Trust for Ornithology, said “This is a surprising and worrying decline in Skylark numbers, which had been holding up well in Scotland until recently. BBS results are crucial in understanding the causes behind bird declines, and we owe this information to dedicated volunteer birdwatchers across the country.”
Dr Andy Douse, ornithologist at Scottish Natural Heritage, added "The report highlights the invaluable contribution to bird monitoring made by volunteers. The results provide SNH with a fascinating picture of how our common birds are faring in Scotland, but we are also conscious that better coverage is needed in our upland habitats. SNH will be working with BTO to improve this in the coming years.
Professor Jeremy Wilson, Head of Conservation Science at RSPB Scotland, said: "The Breeding Bird Survey gives us crucial conservation insights into the fortunes of Scotland's birds over the past 15 years. Increases in the population of some summer migrants such as swallows, house martins and whitethroats are welcome, but urgent action is needed through agri-environment schemes to addres the declines of waders such as lapwing and curlew. The 64% decline in Kestrel population since 1995 is especially worrying and RSPB is beginning research on this species to diagnose the causes."