Photographer Paul Why has posted this fascinating encounter on the HNHS Flickr website.
26th July 2012, Broxbourne Wood, Hertfordshire, UK.
Three days after finding a Purple Emperor in the car park at Broxbourne Wood I was back there for another look, partly because they're the most exotic insect I know where to see locally and partly to try to gauge whether the recent clearance work might have affected their numbers.
The photo (right) shows Broxbourne Woods earlier in the season.
Two hours of searching had been unsuccessful. Then while sitting on the small seat near the top of the main ride I heard some flapping, and saw the shadow on the ground of something large behind me. Initially I thought this was a dragonfly, as there were quite a few around, but when it flew in front of me I realised it was what I'd come to see. It circled my head very closely three or four times, then landed on my face. I reached out slowly to try to grab my camera, which was on the seat beside me, hoping for a record shot (after all, who would believe me otherwise?), but before I managed it he took off again towards the top of the ride.
I followed, more in hope than expectation, but he again circled me, then landed on my trouser leg. This time I was ready, and managed to grab a few shots before he was off again. He landed a couple of times to probe the ground, but despite my keeping a safe distance he didn't properly settle.
On seeing the photos at home on a large screen, I noticed that the notch on his left forewing exactly matched that on the specimen I'd seen three days earlier, in the car park, over 500 yards away. It makes me wonder just how many separate sightings within the wood are of the same individual, and how overestimated the species population here might be.
Analysis of the Purple Emperor populations in Hertfordshire based on surveys by Liz Goodyear and Andrew Middleton were published in the HNHS journal The Hertfordshire Naturalist in 2011 and 2008