Rare Butterfly Revival in Wales as Landowners Adopt Hedge-Friendly Practices
Record numbers of eggs from the rare brown hairstreak butterfly have been discovered in south-west Wales this winter, marking a significant recovery after more than a decade of decline. This upturn is attributed to landowners and farmers cutting back on the mechanical flailing of hedgerows and scrub, which had previously devastated populations.
Decade of Decline Reversed Through Conservation Efforts
In areas like the Tywi valley in Wales, populations of the brown hairstreak butterfly had almost disappeared due to aggressive hedge management practices. The butterfly lays its eggs on blackthorn bushes every summer, but when hedges are mechanically flailed each autumn, thousands of these eggs are unintentionally destroyed. Conservationists have successfully persuaded landowners to adopt a more gentle rotation system, leaving sections uncut for up to three years to allow eggs to survive over winter.
This approach enables caterpillars to emerge with the foliage in spring and hatch into adult butterflies by July. The brown hairstreak is notoriously difficult to spot as a butterfly, so volunteers assess populations by counting its minuscule cream-coloured eggs on bare blackthorn branches during winter months.
Record Egg Counts Signal Promising Recovery
Volunteers from Butterfly Conservation conducted egg counts this winter and found remarkable results. On the north verge of the busy A40 west of Llandeilo, they counted 276 brown hairstreak eggs, while the south verge yielded 117 eggs. Both counts represent record numbers and a 50% increase compared to the previous year. Additionally, three nearby hedgerow sections showed increases following sympathetic management, including the planting of new blackthorn bushes.
The conservation efforts began in 2021 when Butterfly Conservation identified a small remnant population west of Llandeilo. They initiated annual egg counts and collaborated with the National Trust and the South Wales Trunk Road Agent to plant more blackthorn and protect hedgerows from annual flailing. In contrast, a nearby group of fields that continued with traditional flailing practices saw egg counts drop from an average of 60 per winter to just four this year.
Conservationists Celebrate Positive Trends
Richard Smith, a volunteer overseeing the conservation efforts for Butterfly Conservation, expressed excitement about the findings. "The West Wales volunteer team of BC's South Wales branch are really excited to find that, after a decade of heartache for brown hairstreak butterflies in Carmarthenshire's Tywi valley, there is at last signs of an upturn," he said. Smith highlighted that the Welsh government's new sustainable farming scheme requires avoidance of annual flailing, which aligns with their conservation goals.
Dan Hoare, director of nature recovery for Butterfly Conservation, emphasised the broader ecological importance of hedgerows. "Across the UK, hedgerows are an essential part of our ecological infrastructure, providing homes and highways to millions of insects, mammals and birds," he noted. Hoare pointed out that since the 1950s, about 40% of hedgerows have been lost, with less than half of the remaining in good condition. He encouraged landowners to reduce cutting frequency, suggesting that trimming every two or three years could make an enormous difference for species like the brown hairstreak.
Future Prospects and Sustainable Practices
The recovery of the brown hairstreak butterfly serves as an indicator of balanced land management. Conservationists plan to continue working with the Welsh government and local hedge-layers to maintain this positive trend and ensure the species' survival in the valley. This case demonstrates how small changes in agricultural practices can have significant impacts on biodiversity, offering hope for other wildlife species facing similar threats.
