Our thanks to Roger Smith (87 and bright as a button) and his intrepid friends for the following info from Dorset.
There seems to be a population around Minterne Magna, north of Cerne Abbas. Singletons have been seen three years running in Minterne Magna gardens, including two together on Aug 2nd. There are no large woods in this area, but a matrix of copses and wood belts. Sallow consists almost exclusively of narrow-leaved varieties.
On July 17th this year one male was seen at Deadmoor Common, near to where one was seen in 2009. Again, the sallow resource consists almost exclusively of small-leaved narrow-leaved sallows (Salix cinerea).
In addition, the butterfly has been seen for the last three years near Newtown in Cranborne Chase, with a max of 10 on a day in mid July this year. This is despite loss of sallows due to forestry work.
Finally, one was seen almost in Hampshire near Alderholt on 8th Aug.
Dorset continues to establish its Purple credentials.