Brown Hairstreak butterfly recovering – Report your sightings

Brown hairstreak. Credit Roger Wasley

August 2011. A survey of ash trees in east Worcestershire organised by West Midlands Butterfly Conservation has so far confirmed four new trees used by the nationally rare brown hairstreak butterfly.

Amongst the new trees is one on the Naunton Court Fields nature reserve owned by Worcestershire Wildlife Trust. The butterflies assemble around ash trees shortly after they've emerged and it's here that breeding takes place.

Mike Williams, Brown Hairstreak Champion for Butterfly Conservation, explained "While we know that ash trees form a very important role in the life of Brown hairstreaks so far we have identified relatively few of the trees involved.

Big Ash Bash
"The aim of the Big Ash Bash this year has been to try to fill this gap in our knowledge and we are delighted with our success in finding several new trees. Our volunteers have been making early morning visits to a number of ash trees in the hope of spotting this elusive butterfly.

Grafton Wood
"The stronghold for the butterfly in the entire Midlands region is Grafton Wood at nearby Grafton Flyford. Together with the Wildlife Trust, we've been working with local landowners and communities throughout the ancient Forest of Feckenham to improve habitats for the butterflies.

"Over the last 5 years we've seen both their population expand in numbers and in range. To discover that they've successfully colonised ash trees in Naunton Beauchamp as well as trees in Bradley Green to the north and Rous Lench to the south is absolutely brilliant news."

Brown Hairstreak habits and lifecycle
The butterflies are a national priority for conservation. They spend a lot of time in tree canopies and are often hard to spot. From late August female Brown hairstreaks will descend to hedgerows to lay their eggs on young blackthorn. The eggs remain on the blackthorn throughout the winter months and hatch in early May.

The caterpillars feed on the blackthorn leaves before descending to the ground to pupate. They emerge as butterflies in July to feed, mainly it is thought, on the honeydew secreted by aphids.

Hedgerows
James Hitchock, conservation officer for Worcestershire Wildlife Trust, commented "This is really great news and proof that our joint efforts to help this species are working. Much of the work we do with other landowners is about advising on appropriate hedge management to help the butterflies survive and expand their range.

"We often take hedgerows for granted but they're essential corridors that can help wildlife move through our countryside. The butterflies have now been found now on eight of our nature reserves as well as many other sites in the area. This is a real conservation success story."

Report sightings
The two conservation organisations are hoping that members of the public can provide more information about the location of Brown hairstreak butterflies. They're asking people to get in touch if they think they've seen brown hairstreak butterflies congregating around ash trees.

The best time of day to see them is in the morning between about 7.30am and 9.30am. Anyone who thinks they've spotted them should contact Mike Williams on 07802 274552 or by email on mike@stagborough.fsnet.co.uk

Brown Hairstreak Day
The two charities organise an annual Brown Hairstreak Day at the end of August to look for the female butterflies who descend to lay their eggs. This year's event takes place on Sunday 4th September and anyone interested in taking part should contact John Tilt on 01386 792458.

To help Worcestershire Wildlife Trust protect our natural habitats and wildlife, visit www.worcswildlifetrust.co.uk for information about their work and becoming a member. For more information about the work of Butterfly Conservation visit www.butterfly-conservation.org