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Brown Hairstreak in Worcestershire - Bulletin 4

February 2005

Dear Brownhairstreakers,

Welcome to our 4th ebulletin.

Thanks to the hardy and intrepid group that defied the elements on Sunday, we have now virtually completed the core egg count for this year. Again, we found excellent numbers of eggs especially on the blackthorn scrub on the eastern side of the orchard where the egg count was the highest in 15 years of monitoring. A number of us spent the Sunday morning planting 70 blackthorn whips along the edge of the main north-south ride in Grafton Wood which we hope will provide new breeding habitat. This work was funded by the Environment Agency through their Action Earth campaign co-ordinated by CSV to whom we are very grateful. It has been very encouraging to see the impact of our management work in encouraging Brown Hairstreaks to breed within the wood itself. Opening up rides and re-establishing a coppice rotation has enticed the butterfly to come into the wood and the new planting will supplement the natural regeneration of blackthorn that is already taking place. The other thing we tried to do on Sunday was mark several blackthorn plants both within the reserve and along the edge of the orchard that held reasonable numbers of eggs. By doing this, we hope that it will assist us to locate larvae in the spring as part of a new population study we are planning. There have been relatively few studies undertaken on the larval stage of the Brown Hairstreak, partly because caterpillars are extremely well camouflaged and therefore difficult to find in the wild, so hopefully our tagging of promising plants will help to overcome this problem. We shall be looking for local volunteers to assist with this work which will involve repeat visits over a period of several weeks to monitor caterpillar development and survival. If anyone is interested in helping with this important work let me know. If there is sufficient interest, we will hold a training event in April.

Although the core area count is now complete, this does not mean that we can rest on our laurels (or should that be blackthorns) as we are keen to continue with our work mapping the distribution of the Brown Hairstreak in the wider area. We are wondering about meeting up this coming Sunday morning with a view to trying to target some of the missing squares and perhaps if people are available they could let me know. If people want to have a try independently, the up to date distribution map is now on the West Midlands Butterfly Conservation website www.westmidlandsbutterflyconservation.org.uk but please let me know what squares you intend to target so that we do not duplicate effort.

Thinking ahead to the Summer, we have already diaried a number of Brown Hairstreak related events which we hope people will be interested in attending. Further details will be available nearer the time but people may want to make note of the dates. On Sunday, 31st July we are hoping to get out and about to look for male Brown Hairstreaks and identify the particular trees on which they congregate. Males generally emerge in advance of the females and are thought to set up territories in prominent trees, mainly ash, seldom returning to ground level. Certainly, it is very rare to spot a male Brown Hairstreak, most adult sightings tend to be females involved in egg laying on blackthorn bushes. We managed to identify a couple of these 'muster' trees last Summer and we are keen to find out whether the same trees are used from year to year. This is a little studied aspect of the butterfly's life cycle and should prove very illuminating. Obviously, if there are key trees used annually by the males it will be important to identify these and make sure they are retained. The following weekend on Sunday, 7th August we shall be managing blackthorn scrub in a private woodland where the owner has done a superb job over the years in creating Brown Hairstreak habitat and has provided a model on how woodland can be managed both commercially and for wildlife. Late July/early August is the best time of the year to manage blackthorn as it is the only time when eggs or caterpillars are not present. Finally, on Sunday, 4th September we shall be holding our annual Brown Hairstreak guided walk starting from the Three Parishes Hall at Grafton Flyford. Full details are on the West Midlands branch website and more information will also be provided via this ebulletin nearer the time.

Do let me know about this coming Sunday if you can come and I will send out meeting arrangements.

Best Wishes,

Mike Williams,
Brown Hairstreak Champion,
West Midlands Butterfly Conservation