Brown hairstreak butterfly eggs found at Worcester nature reserve 

The brown hairstreak butterfly was almost extinct in the region but is now expanding its range thanks to conservation efforts.

Volunteers from the West Midlands branch of Butterfly Conservation have been working with land managers, including Worcestershire Wildlife Trust, to help the small and elusive butterflies move into new areas.

A recent search of Lower Smite Farm uncovered five eggs and Trust volunteers have since found another four, three of which had been laid together, a rare occurrence in itself. Last year, a single egg was found at the reserve.

The brown hairstreak only lays its eggs on young blackthorn, with caterpillars feeding on the young buds of the plant when they hatch in spring.

In the 1970s, Grafton Wood in east Worcestershire was one of only a few places in the UK where the butterfly could be found. But sensitive land management, including cutting hedgerows on a three-year rotation, has allowed the brown hairstreak to expand across the county.

It was thought the M5 was a barrier to further expansion to the west until the discoveries at Lower Smite Farm.

Caroline Corsie, senior land advisor from the Trust, said: “We’ve been watching the incredible success that Butterfly Conservation volunteers have been having in helping this beautiful butterfly to spread into new areas. It’s now found on ten of the Trust’s nature reserves. 

“We’re delighted that brown hairstreak butterflies have found our hedgerows to their liking too. It’s early days but we’re looking forward to seeing more eggs in future years – the adults can be even harder to spot.” 

Simon Primrose, the brown hairstreak champion for Butterfly Conservation in the West Midlands, said the eggs were found in four different 1km squares, suggesting the butterfly is established across the site.

“It’s taken some time for the butterflies to make their way across the M5 so we’re really pleased to have such positive confirmation of their arrival in this part of the county.”