BACK__________________________________________________________________________________________________
BACK__________________________________________________________________________________________________
August 2011
Dear Brownhairstreakers,
Although it is only a short time since the circulation of the last
ebulletin so much has been happening over the past couple of weeks that a further
update on the season seems timely. First and foremost to report is the continuing
success of the Big Ash Bash with a further three Brown Hairstreak Assembly Trees
confirmed by Hugh Glennie. Two of them are on the Worcs Wildlife Trust reserves
of Naunton Court Fields and Piddle Brook Meadows and the third along the Wychavon
Way west of Rous Lench. A group of us went out to have a look at the new trees
on 10th August and, despite rather cloudy and cool conditions, recorded a hat-trick
of Hairstreaks with good views of adult males at all three sites (see photo).
With two or three other possible trees still to confirm, I think
we can confidently predict that the number of known assembly trees is set to
almost double by the end of the month. The survey, while adding considerably
to our knowledge of the whereabouts of assembly trees, is also providing useful
evidence regarding the types of trees selected and some of this information
will enable us to ultimately review some of our current ideas regarding Brown
Hairstreaks. I received recently a very interesting email from Tom Dunbar who
has discovered many assembly trees over the years in Oxon/Bucks and he observes
that often the trees chosen by Brown Hairstreaks are also favoured by other
insects including bees, wasps and flies. He suggests that high levels of insect
activity around ash trees are a good indicator that the tree might be utilised
by Brown Hairstreaks and that he has used this technique to identify new trees
in the past. Certainly, we have already found this to be the case with the Big
Ash Bash with many of our new trees being frequented by Purple Hairstreaks,
Speckled Woods and other insects. The question remains as to what attracts insects
to particular trees in the first place. The textbook answer is of course aphid
secretions, sometimes known as honeydew, but Tom and others are somewhat sceptical
about this and, like many things in the natural world, things are probably more
complicated than they at first seem. Numbers of Hairstreaks on assembly trees
should build up over the next fortnight as more females begin to emerge so there
is still plenty of time to search for new trees. Sunny and warm mornings are
the best time to spot Brown Hairstreaks from 7.30 am through to around 10.30
but providing the temperature is warm enough (ideally 20+C) there is a good
chance of activity even where little sun, so do get out there and take a look.
We are keen to hear of any new trees spotted and also any observations you make
of Brown Hairstreak behaviour on the trees.
Despite the very early sighting reported in the last ebulletin,
the season seems to have been fairly typical with the main emergence of males
not coming until the end of July. Weather statistics show that minimum temperatures
during the month were the coolest since 1965 which probably slowed the season
down. We had to wait until 9th August for the first female Brown Hairstreak
reported by John Tilt at Grafton Wood NR and since then there have been several
sightings in and around the wood. Males have also been recorded nectaring on
angelica and knapweed but most sightings have been in trees. A first for Worcs
was the sighting of a male and female in cop high in the assembly tree at Stock
Green by Martyn Ganderton and John Tilt on 14th. Too far away sadly for a photo
but clearly visible through John's telescope. John reports that the female flew
away leaving the male sitting on the same leaf but he couldn't be sure whether
the male was smoking a cigarette or not! Now that females are on the wing, overall
numbers are beginning to build up nicely. A visiting BC member from Cheshire
had six sightings of Brown Hairstreaks on the western side of Grafton Wood last
weekend and most other visitors seem to have also been successful in obtaining
photographs. Egglaying is now underway and Paul Meers sent through a mystery
batch of eggs that he photographed on the underside of a blackthorn leaf at
Feckenham Wylde Moor (see photo). Clearly not Brown Hairstreak eggs and if anyone
has any ideas on their identification I would be pleased to hear from them.
We had a record turnout for our Blackthorn Bash at Bob Steele's
wood on 7th August and managed to get a fair amount of work done along several
rides. A big thank you to all those who turned up, including several new faces,
and also to Bob, Sue and other family members for the usual excellent lunchtime
refreshments. Lots of butterflies around while we worked including a fresh Brown
Argus but no Brown Hairstreaks this time. One way or another we seem to spend
a lot of our time around trees and the Brown Hairstreak is generally considered
to be a species associated with woodland. It has always been, therefore, something
of a mystery that the butterfly appears well distributed south of A422 where
there is very little woodland. Recent research by Simon Primrose, however, has
shown that this was not always the case. As the map shows, the original boundaries
of the Forest of Feckenham extended as far south as Evesham far beyond the current
known distribution of the Brown Hairstreak which Simon has circled.
.jpg)
Clearly, not all of this area would have been extensively wooded
and it would be interesting to discover the actual extent of woodland cover.
Perhaps some of the very isolated assembly trees we have been discovering in
this area formed part of a much more wooded landscape in the past. Those of
us who are active volunteers with the Wildlife Trust will have received an invitation
to this year's Reserves Conference on 17th September. One of the speakers is
Adam Mindykowski from the County Council who is giving a talk on the historical
environment and landscape of the Bow Brook which falls within the Forest of
Feckenham so may be this will provide some of the answers.
The next big event on the Brown Hairstreak calendar is of course
the Open Day on Sunday, 4th September based at the Three Parishes Hall in Grafton
Flyford. The event starts from 10 am and there will be guided walks into Grafton
Wood with the hope of seeing the butterfly. We have found that organised group
visits like this increase the chances of seeing Brown Hairstreaks so, if you
have been previously unsuccessful or have never had a good view of the butterfly,
this day offers a great opportunity to break your duck. There is no charge for
the event and refreshments will be available in the village hall lunchtime.
There will also be various displays and a sales stall. Look forward to seeing
people there but in the meantime do let me know of anything of interest you
come across.
Mike Williams,
Brown Hairstreak Species Champion,
West Midlands Butterfly Conservation