BUTTERFLY
CONSERVATION UPPER THAMES BRANCH
WOOD WHITE ANNUAL REPORT - 2006
Becky Woodell
Wood White
(Photo
© Nick Bowles)
SITE REPORTS – UPPER THAMES REGION
Wood Whites were
recorded from eight sites in the Upper Thames region as follows:
Date Site #
Observed
23 May College Wood one
23 May Salden Railway five
05 June Whitecross Green eight
Peak transect number
07 June Salden Railway fifteen
07 June Whitfield Wood two
18 June New site one
Grid Ref supplied
24 June Leckhampstead Wd two
29 June Wicken Wood twelve
Bucks section; includes two en.cop.
I had not included College Wood in the list of current sites following
the surveys in 2002 and 2003 because no Wood Whites were found there. Therefore
we have eight localities instead of the seven recorded in 2003. Leckhampstead
and Wicken Woods, although in separate ownership are all one woodland. However,
Leckhampstead Wood was previously so overgrown that no Wood Whites were found.
Thus, the size of the habitat there has increased.
Salden
Railway Cutting
Stuart Hodges and I visited this disused railway on 7 June in good
weather. We first looked at the area southwest of the road bridge at SP831311.
It is a small area which is currently good for Wood White, but is likely soon
to become too shaded. The area is rather small, becoming wooded and shaded to
the southwest. A total of 13 Wood Whites were seen here. Two food plant species were seen. Meadow
Vetchling was rather rare but Birds-foot Trefoil was frequent. Other species
seen were Common Blue (13), Green-veined White (1), Grizzled Skipper (2),
Orange Tip (2), Large White (1) Small Copper (1), Burnet Companion (6) and
Cinnabar (3).
Stuart and I walked northeast under the road
bridge past Salden Wood toward the Newton Longville road bridge. Beyond the
wood the cutting widened out, becoming nearly level with the adjacent land.
This open area is botanically rather species rich. Two further Wood Whites were
seen. Other species were Small/Green-veined White (7), Orange Tip (5),
Brimstone (7), Common Blue (14), Brown Argus (1), Peacock (1), Burnet Companion
(14), Latticed Heath (1).
I have since talked to Roy Maycock, Bucks
Botanical Recorder who knows the area
which was surveyed by BBOWT (BBONT) in 1986. He confirmed that all of
the line still belongs to Railtrack. There is pressure to reopen this line and
link up Milton Keynes with Oxford via Bicester. Roy thought it was not impossible.
Whitfield Wood
Stuart and I also visited Whitfield Wood on 7
June, weather sunny and hot. Two Wood Whites were seen. The wood is small and
narrow and is suffering seriously from eutrophication with a lot of cleavers,
nettles, etc. Meadow Vetchling is
common but the rides are very overgrown with dense grasses and do not look a
promising habitat. Other species seen were Large White (1), Common Blue (2),
and Silver –Y (1).
Little Linford Wood
Phil Sarre, the BBOWT Warden has no confirmed
records for this year. They are usually seen although in very low numbers.
College Wood
The sighting here is good news as none were
reported for several years after the Woodland Trust purchased it and undertook drastic
‘opening’ of the central ride in the winter of 2001-02. We now have singles for
2005 and 2006. This is an important site to watch as conditions may now improve
and it could become a good spot again.
New Site
A single Wood White, confirmed by a photograph
was recorded in a new site in north Oxfordshire. Due to site sensitivity during
the breeding season we are currently withholding Grid References. I will visit
in the coming flight season.
Whitecross Green Wood
Wood Whites had a poor season here. The annual
index is 25, second worst after 24 in 1998.
The first transect date is 2nd June (6 seen). The peak
transect count is 5th June (8 seen) and the last transect date is 8th
July (1 seen).
The first Visitor’s Book date is 29 May when 3
were recorded. The signature looks like B. and M. Raymond who came for a walk.
If anyone knows the Raymonds I would be grateful if you could contact me. They ticked the ‘BBOWT Member’
heading in the Book so might also be UTB members. I did a transect on the
afternoon of the 28th and saw no Wood Whites but they might have
emerged then or on 29th. Three would fit better with an emergence
date than the six I saw especially as they peaked at eight.
Visitor records continue until Steve Woolliams
whom I know, saw one on 8 July which ties in with the last transect date on the
same day. I saw no more, but some intriguing records appear in the Book which
could be a second brood that I never found.
Does anyone know the following people?
22 July , Joan Tomkins travelled 70 miles and
saw one; 27 July Steve Lane and David Beer (1), travelled either 20 miles or
70; 31 July Meg Pollitt and Mike Zeyfect (?) from Oxford (3). Confirmation of
these records would be very valuable. Can anyone help?
The above does show the value of regular and clear entries in the
Book. Sometimes there are no entries for several days although I see good
numbers of visitors.
THE WIDER COUNTRYSIDE
I have contacted two other people who monitor
Wood Whites.
Stephen Jeffcoate monitors Oaken Wood in
Surrey. This wood has a good population, although numbers were down in 2006 but
not as low as 1993 or 1994. I spoke to
Stephen just before he went away for a while so will contact him later to see
if we can get some more exact information by looking at his figures for these
years.
Andy Patmore is a forester who monitors Wood
Whites in several Forestry Commission woods in Northamptonshire. He does four
transects a year in each wood during
the Wood White flying season and regards 2006 as one of the lowest years he has
recorded. He says Wood Whites have cycles of peaks and troughs. In his sites the worst slump was 1998 with
another in 1993. They built up again in 1994–96 and 1999-2004.
Below is a graph of the annual Indices at
Whitecross Green since transects began in 1986. The lowest numbers occurred in 1986, 1994 and 2006 with peaks in
1990, 1995, 2002 and 2004. Compare the
Whitecross graph with the information from Oaken Wood and the Northamptonshire
woods. On the basis of these figures my
hypothesis is that Wood White populations, as with other Lepidoptera species
are influenced by climate/weather while local habitats and management can
ameliorate or worsen the effects.
Thank you to everyone who has provided records
or searched without success. Please keep looking in 2007 and remember that for
this species a negative result during the flight season can be as important as
a positive if you are in a known or previously known site.
Thanks to Cliff Cooper and Tony Croft without
whose patient technical help this report would probably have been written by
hand. Special thanks to Stuart for ensuring that I never became irrevocably
lost in the wilderness of Bucks woodlands.
Becky Woodell, February 2007
