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Brown Hairstreak in Worcestershire - Bulletin 77

January 2011

Dear Brownhairstreakers,

Thank you to those who joined us on the egg hunt on 3rd January. We had a good turnout and, fortified by mincepies and mulled wine, managed to complete the count of the majority of the core area around Grafton Wood. We were pleased to be joined by Maisie Jepson, this year's Brown Hairstreak student from Exeter University, who has been working hard surveying hedgerows on a number of local farms and making some good contacts with landowners. Eggs were found in pretty good numbers and, with only the southern section of the wood still to search, it looks as if we are on track to exceed last year's total which in itself was an improvement on the previous year. We are also grateful to Rob Mabbett and his team who have again completed the count in an area of privately owned woodland which has been monitored over a long period and this similarly produced the best total for three years. Two interesting observations from the data collected from Grafton so far, is the number of multiple egg clusters found and the large percentage of eggs found on suckering growth. The majority of Brown Hairstreak eggs are always laid singly but occasionally one finds two or more eggs laid together. This was very noticeable in our search, with a number of 'trebles' found and many more 'doubles' than normal. Already, we have recorded more 'trebles' than in the previous 3 years combined, although why this should be the case is hard to understand. It would be interesting to hear whether this is purely a Worcestershire phenomenon or whether other recorders have noticed this elsewhere in the country. The importance of sucker growth to Brown Hairstreaks is illustrated by the fact that so far 67% of the eggs found have been on blackthorn less than 2 foot in height. I feel sometimes that, while we rightly emphasise the importance of cutting blackthorn hedges on rotation, we need to give equal emphasis to the importance of protecting sucker growth at the base of the hedge particularly where there is stock in the adjacent fields. This coming Sat, 15th January sees our fourth organised egg hunt of the season when, with a decent turnout, we should be able to complete our core count around Grafton Wood. The meeting place as usual is outside Grafton Flyford Church (just off A422 Worcester-Stratford road) at 10 am. All being well, we shall meet again a fortnight later on Sat, 29th January when, footloose and fancy-free, we will be able to widen out our search to take in so far unrecorded 1 km squares. Harry Green, editor of the Worcs Biological Records Centre newsletter, approached me recently to ask if I could do an update on the article on the Brown Hairstreak which appeared nearly 5 years ago. Looking back, I notice that the number of known squares then had just topped the hundred mark, we are now up to 166 with hopefully a few more to add before the end of the winter, which is testament to the continuing commitment shown by our local champions and other volunteers in mapping the butterfly's expanding distribution.

Both Simon Primrose and myself, both separately and jointly, have been doing our best in recent weeks to add to the total but so far without success. Simon has been concentrating mainly on squares in western Warks, but also around Redditch, while I have been trying to turn the Waitrose One into the Waitrose half dozen by searching for eggs in squares around Droitwich. Yesterday, after making a very productive farm visit in Cladswell with Richard Southwell, I walked a stretch of the Droitwich Canal from the point where it joins the Worcester-Birmingham but found very little blackthorn. Today, along with Simon, we looked at fields to the east of Peopleton concentrating on the square to the south of the Cowsden assembly tree which is still eggless despite various attempts over the past two years. I had to leave early but Simon walked the full length of the footpath towards Cowsden but the only eggs found were in close proximity to the tree itself and in an already recorded square. Martyn "I have an assembly tree in my garden" Ganderton has also found several eggs around Stock Green, including on damson suckers in his garden which is an interesting observation. While most eggs are laid on blackthorn, over the years we have found several eggs on other Prunus species including Bullace and Damson.

John Tilt, the Reserve Manager at Grafton Wood, and myself went down to a nursery at Newent last week to collect nearly 2,000 blackthorn plants together with 20 disease-resistant Elm trees. We already have a growing list of farms requesting blackthorn for planting and, if you are interested in this, please get in touch on 01386 792458 as soon as possible. The blackthorn plus rabbit guards are completely free and ready for planting. At the moment, they are taking up rather a lot of space in John's garden so he is keen to move them on!

Hope to see some of you on Saturday.

Mike Williams,
Brown Hairstreak Species Champion,
West Midlands Butterfly Conservation