A new study has shown that growing a special seed mix may provide a lifeline to one of Scotland’s most rapidly declining species of bird, while also delivering benefits for farmers.
Sowing a green manure seed mix in autumn can provide safe places for corn buntings to nest, while improving soil condition on farms, RSPB Scotland said.
The conservation-focused charity has called on the Scottish Government to include autumn-sown green manure in future agri-environment schemes as soon as possible.
Once widespread across the UK, corn buntings have suffered huge declines.
In east Scotland, numbers plummeted by 83% between 1989 and 2007.
This made them one of Scotland’s fastest declining species.
Work by farmers in Fife and Angus has dramatically improved their fortunes there.
By growing wild bird seed mix, farmers have provided three key things corn buntings need: seed food in winter; insects to feed their chicks in spring; and safe nesting sites.
Further north, reversing declines has been harder as the main challenge is safe nesting.
Late nesters a challenge on farms
Corn buntings tend to favour grass silage fields. Because they nest late and on the ground, this puts nests at risk of destruction at the egg or chick stage when fields are mown, typically in June.
There is an Agri-Environment-Climate Scheme (AECS) option that pays farmers to delay mowing until August, but this has drawbacks.
RSPB Scotland said: “The quality of forage is significantly reduced by mowing this late.
“It is not a popular option for farmers to choose.”
But research on six farms in north-east Aberdeenshire suggests autumn-sown green manure crops may be another option.
Nest survival was 60% in the field trial plots. This was similar to nearby cereal fields (70%) and much better than nearby grass fields, where the survival rate was just 25%.
RSPB Scotland senior conservation scientist Allan Perkins said: “Silage fields may act like a trap. Corn buntings are attracted to them in May and June to nest.
“But then around the time eggs are hatching. and nearly always before chicks can fly. the fields are mown.”
Little appetite for delayed mowing
Previous research showed not mowing until August 1 is effective at increasing nest survival sufficiently to halt declines.
Mr Perkins added: “Agri-environment payments have been available for this since 2008.
“However, because the quality of forage harvested declines with later cutting, the uptake of this has been low.
“An additional option that works for more farmers is badly needed if we are to halt and reverse declines in this once common species.”
Green manure crops are a popular AECS option for farmers across the UK, RSPB Scotland said.
It added: “Grown in rotation, they can dramatically reduce dependence on manufactured fertilisers and help alleviate soil compaction, erosion and water pollution.
“These crops include clovers, vetches and phacelia – which all provide a rich source of pollen and nectar for pollinating and predatory insects too.
“Such insects can provide additional benefits to farmers via the pollination of crops and pest control.”
In Scotland, the uptake of a spring-sown green manure AECS option has been high.
RSPB Scotland said this suggests that an autumn-sown option may also be popular.
Conversation