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Brown Hairstreak in Worcestershire - Bulletin 6

April 2005

Dear All,

Sorry not to have sent round a bulletin for a while but I have been waiting until all our egg data for the winter was to hand. As predicted the 2004/5 season proved to be an all time record for eggs. Our core area count, which is the area immediately around Grafton Wood with data stretching back all the way to 1969/70, was the highest in thirty-five years of monitoring; the next best years being 2001/2, 1994/5 and 1992/3. This core area remains unchanged each year to ensure consistency of results but over the years, we have started to count eggs in other nearby hedgerows and areas of blackthorn including, for the first time this year, three rides within the wood itself. Taken together these counts have produced a phenomenal 926 eggs! On top of this figure, of course, are all the eggs discovered in the wider countryside as part of our searches aimed at expanding our knowledge of the full range of the butterfly making the prediction in Bulletin 3 of a 1000 eggs pretty close to the mark. Thanks to everyone for their help in reaching this impressive total.

As mentioned in Bulletin 4 we intend to have a try at monitoring some Brown Hairstreak caterpillars this year and have marked up some eggs in fairly accessible spots in preparation for this. Our colleagues in Butterfly Conservation's Upper Thames branch, who have been monitoring larvae over the past two years, say that the earliest date they have found a hatched egg is 9th April so there is not long to wait. On emergence, the caterpillars burrow into the leaf buds of the blackthorn and are virtually impossible to see but, after their first skin change, they begin to browse more openly on blackthorn leaves. Hopefully, this may coincide with the date of this year's Grafton Wood Open Day which is on Sunday, 24th April from 11 am so if there is sufficient interest we can do a special caterpillar crawl as part of the day. For those who have not been before, the annual open day is a great day out for all the family with guided walks all day, stalls, woodland craft demonstrations, a family quiz and delicious homemade refreshments. The wood is usually at its spectacular best with masses of bluebells and other spring flowers and, if the weather is favourable, there should be a few butterflies around as well so well worth a visit. Please email me if you would like to take part in a caterpillar crawl (no actual crawling involved!) or come to the Butterfly Conservation stall at the Three Parishes Village Hall on the day to put your name on the list. We shall be relying on our locally based Hairstreak Champions to assist with this project so please come along on 24th to be 'trained up'.

Best Wishes,


Mike Williams,
Brown Hairstreak Species Champion