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Brown Hairstreak in Worcestershire - Bulletin 11

August 2005

Dear All,

We have lift-off. It is pleasing to report that Worcestershire's Brown Hairstreaks are now officially on the wing. Our Brown Hairstreak event last Sunday provided our first ever confirmed July sighting in the county, although there had been a previous unconfirmed report the previous weekend. The idea of the day had been to identify trees used by male Brown Hairstreaks for assembly. This is something we started on a small scale last year and hope to build on. One thing we are hoping to discover is whether the same trees are used by the butterfly from year to year or whether different trees are favoured each year. If the former, this has important implications for the conservation of the Brown Hairstreak insofar that we may need to focus attention on the preservation of key trees in hedgerows and on the edge of woods, alongside our ongoing efforts to secure appropriate blackthorn management.

Our first priority was to revisit those trees where we had observed activity last year and we enjoyed immediate success. If there is one thing we have learned about Brown Hairstreaks over the years it is their total unpredictability. After having warned people that to locate Brown Hairstreaks this early in the season would be challenging to say the least and that there would be no guarantee of success, we not only located a Brown Hairstreak on the first tree we looked at but within 20 seconds! This was the same tree we had located adults on last year - a smallish ash halfway along an east facing hedgerow about 0.25 mile short of Grafton Wood. Altogether, we found 2 Brown Hairstreaks which we were able to obtain good views of with the aid of a telescope. Both had their wings firmly closed but one was noticeably larger and brighter than the other leading to the conclusion that they were male and female. They were quite high up in the tree and we kept them under view for around 15 minutes but neither moved in that time.

Buoyed by this success, we moved on to the southern edge of the wood where Rob Mabbett and John Coates had observed three adults on an ash last year. This time, however, we were not so lucky and, while Purple Hairstreak was present, there was no sign of Brown. Other ash trees along the western edge of the wood also drew a blank but undaunted we moved on up to the orchard where again we located further Purple Hairstreaks.

Finally, we searched within the wood north of the orchard and hit the jackpot with a single female Brown Hairstreak basking with its wings open high in an ash on the edge of the glade. The butterfly was in pristine condition but tantalisingly out of range from a photography point of view. A careful search of the tree and adjacent ash, however, failed to locate further adults so it is perhaps, in the absence of males, a moot point as to whether we can describe this strictly as a new assembly tree. Returning to the car park, we stopped off briefly at the first tree but the original pair had moved from their respective perches and we were not able to relocate them. We did, however, spot a Brown Hairstreak in flight, possibly the original or another female, descending from the tree and disappearing along a hedgerow out of view.

All in all, a successful morning although as usual with Brown Hairstreaks providing as many questions as answers. Certainly, one thing we learned is that one should certainly start looking for Brown Hairstreak adults before the end of July and also that it is wrong to assume that any Brown Hairstreak up in the canopy is likely to be male. Out of the three confirmed sightings on Sunday, two were female and only one a probable male.

Our next chance to look for Brown Hairstreaks is this coming Sunday, 7th August when we will be undertaking blackthorn management in a private woodland north of Grafton which is being specially managed for the Brown Hairstreak. We are meeting at Grafton Flyford church at 10.00 am prompt to drive on to the site so do come along if you are free. Lunchtime liquid refreshments will be provided and there will be a chance to look round the site.

Hopefully, see you there.

Regards,


Mike Williams,
Brown Hairstreak Species Champion