As a birthday present work
colleagues thoughtfully bought vouchers for me to go on a purple emperor
butterfly safari at Knepp. Despite
several previous attempts I have not seen a purple emperor.
 |
| Male purple emperor. Photo: Martin Landy |
What makes Knepp landscape so special? It is part of a re-wilding experiment. In
2004 internal farm fences were removed and fallow deer, longhorn cattle, Tamworth
pigs introduced at low stocking densities and allowed to graze where they will. So in a way an undirected conservation
project, just wait and see what happens. This has developed under the influence of Frans Vera whose theory was
that the wild wood was not continuous cover but much more of a savannah like
landscape of extensive open and interconnected glades maintained by grazing
animals surrounded by scrub and high forest. The livestock is in commercial meat production but I suspect the real
commercial add-on is the development of several types of wildlife safaris, honesty
box shop and campsite.
This particular safari was lead
by the duo Matthew Oats, National Trust, and Neil Hulme, Sussex Butterfly Conservation,
both great observes of butterfly behaviour. We were also joined by Frans Vera who was
pleased to show us regenerating oaks protected from grazing long horn cattle by
a mantle of surrounding thorny shrubs, and Charlie Burrell, 10th Baronet of Knepp, the land owner
“Did anybody really have to leave
at 3pm?” was the first question as these were great enthusiasts and the
emperors will fly until the early evening if warm enough. Matthew Oats was later checked out by a
purple emperor whilst having an open air bath at Knepp’s campsite. Re-wilding was not about the species but
human reconnection with nature.
What has happen with this
re-wilding experiment? The numerous
small fields lined with hedgerows containing majestic oaks have been invaded with
sallows. This is a perfect habitat for
the purple emperors.
 |
| Purple emperor egg on sallow. Photo: Martin Lan |
The adults can
look brown, purple or blue depending on the angle of light and sometimes look
like they have different coloured wings. The butterflies do not visit flowers but feed on aphid honey dew and sap
weeps on old oak trees. The males claim the
top of the trees as their territory and have dog fights with other males over
poll position there. This is described
as oak topping.
 |
| In poll position on an oak. Photo: Martin Landy |
They also can be seen diving
down to search the sallow, usually in the morning, for the much more elusive recently
emerged empress who will be looking for potential egg laying sites on the
sallow.
Matthew has been a purple emperor
enthusiast for many years. In 1975 he
found about 130 emperors in a whole season across many sites. On 21st June at Knepp this
year he recorded 148 in one day! A British record. Matthew now finds purple emperor numbers
beyond his imagination. The view of the
purple emperor has changed from a butterfly of deep woods to one of a much
broader environment of hedgerows with sallows. The butterfly has been squeezed by
human activity especially against sallows but is now bouncing back.
As we walked around on the tour
Matthew notched butterfly count on his forearm and reached an agreeable count
of 56, with only about 4 recorded as female.
 |
| Matthew Oats keeping a tally. Photo : P. Loughnane |
The bolder white banding of the female gives her away.
 |
| Purple emperor female. Photo : Martin Landy |
We stopped several times to view
purple hairstreak butterflies flying around the oak canopy with Neil being particularly
enamoured by them only to be rebuked by Matthew to “stop hairstreaking’’. Despite the emperors flying 15 metres above us
in the oak canopy, being large butterflies (wing span range male to female: 75-84mm) they were still easily seen,
with the finest views of the males is when they are searching the sallows beneath the oaks. The best view of all was an empress perched
at 2 metres.
At Knepp there are safaris of
general interest and specialist ones with top conservators such as Dave Coulson
on bees and Ted Green on ancient trees. Well
worth a visit and a substantial picnic half way through the full day tour. You will come back enthused!
Paul Loughnane
