Songbirds turn their backs on England . . . to thrive in Scotland
And house martins have increased by 114 per cent in Scotland, but declined by 15 per cent in England, the new annual Breeding Bird Survey shows.
One in three willow warblers have died out south of the Border but the species has soared by 21 per cent in Scotland.
And cuckoos are causing ornithologists serious concern in England, with six out of ten disappearing since 1995, whereas in Scotland the population is stable.
Experts believe the differences could be due to Scotland having more wilderness where the birds can thrive.
Another theory is that conditions in Africa, where each of the birds spends the winter, might be having an impact on survival. Birds from Scotland may migrate to parts of Africa where conditions are better than those to which birds from England migrate.
However, Professor Jeremy Wilson, head of research at RSPB Scotland, believes factors closer to home are more likely to explain the trends.
“The fact that we are seeing differences in Scotland and England suggests that, unless they are wintering in different parts of Africa, there might be differences in the breeding grounds in England and Scotland that explain the changes.
“Maybe climate change is improving conditions in Scotland and making them worse in England. We don’t know if this is the case but there are some interesting grounds for investigating why these birds are doing better in Scotland.”
Kate Risely, Breeding Bird Survey national organiser at the British Trust for Ornithology (BTO), agreed conditions in Scotland were more favourable.
“Scotland has a far lower human population than England,” she said. “There’s a lot more wilderness and you might think a lot of species would prefer a less managed habitat.”
The Breeding Bird Survey is compiled every year by the British Trust for Ornithology, RSPB and the Joint Nature Conservation Committee, with the help of thousands of volunteers.
Other species that have thrived in Scotland over the past 15 years are the great spotted woodpecker, which has seen its population increase by 311 per cent, and the blackcap, chiffchaff and goldfinch, which have all more than doubled in number.
Prof Wilson said: “Songbird populations in Scotland are doing rather well, so it suggests the raptors aren’t having such an impact on them as it’s often claimed they are.”
However, not all species are doing so well. Wading birds have suffered. Lapwing numbers fell by 37 per cent since 1995, half of curlew have disappeared and a quarter of oyster catchers.