www.ukbutterflies.co.uk

Upper Thames BC Branch Brown Hairstreak page:

http://www.upperthamesbutterflies.co.uk ... akPage.dwt

Cheers,

- Pete

Both Upper Thames and West Midlands branches have greatly extended their knowledge of the known range of the species in their areas. Is that evidence that the butterfly has actually extended its breeding range in recent years?

Good question.

I think the answer is "yes and no". The pioneering work undertaken by David Redhead and other members at Upper Thames has provided an excellent vehicle for monitoring this species (i.e. "egg hunts"!). This technique is being replicated in other areas too - including Hants and IOW. In this sense, the answer is "no" - and that we're just recording the blighters more effectively.

However, I did see David's presentation at the Hants and IOW members' day in November, and it was clear that this critter is extending its range into the centre of Oxford, down a "green" corridor containing (of course) blackthorn.

Anyway - look forward to further responses.

Cheers,

- Pete

A very good question and a very good response.

Last winter in Upper Thames we carried out our most thorough egg hunt to date on our only remaining population to the NE of Oxford. We found about 3,500 eggs in a near solid blaock of 178 different km squares. This winter there has been less overall effort and a tendency to concentrate on "blank" squares on the edge of the range and to date we have added another 28 squares representing a 16% "extension" in range. Many of these 28 new squares were searched last winter without success but as we only find a few eggs at most in these peripheral squares we cannot definitely say there presence was not overlooked last year. But my gut feeling is that it is slightly extending its range and if not its definitely straining at the leash.

This weekend we searched the green corrider formed by the River Cherwell down into the centre of the City of Oxford. We found 5 eggs further south than last year and moved it another km towards the centre of the City - now just 1.5km to go to Magdalen Bridge.

David (UTB Brown Hairstreak Champion)