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Brown Hairstreak in Worcestershire - Bulletin 8

May 2005

Dear Brown Hairstreakers,

The combination of a rather unpleasant virus and other commitments has meant that I have not had a chance to get on the caterpillar trail since the Grafton Wood open day in April. The open day itself was a great success but probably a little early in the year to have any realistic chance of finding larvae. Nevertheless, a small group of us did give it a go and, although we found plenty of hatched eggs, of caterpillars there was no sign.

Eager to make amends, I managed to get across to Grafton this morning and I can report at least partial success. I can also report that finding caterpillars compared to eggs is not exactly a stroll in the park! In part, this I am sure was due to varying degrees of inexperience. Firstly, in retrospect I don't think we had marked anywhere near enough eggs. Secondly, marking eggs in mid-April and then refinding them once they have hatched in late May is another matter. A lot of the marked eggs were so swamped in vegetation, it was impossible to relocate the tags never mind eggs and caterpillars. Another year, if we want to repeat the exercise, I think we should go for a hedgerow location rather than fairly isolated blackthorns along woodland rides, and make sure we use larger and more brightly coloured markers. Finally, the gap of a full month since the open day has meant that a lot of caterpillars have no doubt perished in their first and second instars. Anyway, in around two hours searching I did eventually manage to find 3 larvae which I have remarked in the hopes of perhaps refinding them at a later date. I also have a GPS bearing for the locations where I found them, so if anyone else is planning on a visit to Grafton Wood and would be able to do a follow up, let me know and I will pass on the grid references.

The larvae were all less than half fully grown, probably around 8mm in length and were amazingly camouflaged (see attached photo) which was probably another reason for finding so few. In fact, I was very lucky to find my first larva after about an hour's fruitless searching, out on the stem of the blackthorn en route to a nearby leaf (see photo), otherwise I might have drawn a complete blank. This, in itself, was quite an interesting observation as the literature suggests that the caterpillars remain motionless on the underside of blackthorn leaves during the day, only beginning to feed in the evening. Obviously, this particular caterpillar had not read the right book! The other two caterpillars were much better trained and were performing as directed. After this rather humbling experience, I must say my admiration for our colleagues in BC Upper Thames branch has gone up yet another notch as they have had something in the order of 65 caterpillars under surveillance over the last month or so!

Other Brown Hairstreak news to pass on is that we now have a rather splendid information board on the butterfly and its conservation at the main entrance to the reserve and, hot off the press, is a new Brown Hairstreak leaflet aimed at informing the local community about the importance of the butterfly and encouraging local residents to help us save it. Both the board and the leaflet were funded through the Lottery's Awards for All scheme to whom we are very grateful as we also are to Jane Ellis, one of our Regional Officers, who pulled all this together. The leaflet gives various examples of how people can become local Brown Hairstreak champions and there is a tear-off slip to be returned to Butterfly Conservation HQ. Copies of the leaflets are to be circulated with the next Grafton Flyford parish newsletter which is excellent news and we are keen to disseminate as many locally as we can, so if anyone can help us distribute copies please let either John Tilt or myself know.

Hope the above might encourage a few more people to get out looking for caterpillars. If you do give it a go, let me know how you get on. Apologies for those not on broadband, but I hope you will enjoy the photos even if they take a while to download.

Best Wishes,


Mike Williams,
Brown Hairstreak Species Champion