Heather's Nature Notes: CHALK HILL BLUES AND A BIG BUTTERFLY COUNT

Saturday 18 July 2020

CHALK HILL BLUES AND A BIG BUTTERFLY COUNT

Last week, my daughter informed me that she had seen a butterfly on her courgette plants that she could not identify. Her description, brown with a bit of purple on it, and an underwing with a wavy line, fitted that of a purple hairstreak. I suppose it was unsurprising really, seeing as she has a large oak tree at the bottom of her garden; I had often looked at it and wondered about but nevertheless an exciting find.

I was therefore keen to visit her and see for myself, particularly as at this time of year her garden is full of butterflies. Today's forecast was a cloudy morning, though warm so I thought I could also stop off at the NT site of Lardon Chase, near Pangbourne as I wanted to look for some Chalkhill blue butterflies, which are now emerging.

The car park at Lardon chase was almost full at my arrival time of 11.30 am but I just managed to find a space. A short distance from the gate there was a small herd of young cattle but they were more interested in sheltering under the tree than blocking the entrance and I walked close to the hedge to keep out of their way. I could see groups of people walking in this popular area, some picnicking but I was interested in looking for blue butterflies amongst the wild marjoram/thyme. It wasn't long before I found a small blue specimen, but this turned out to be a common blue. It wasn't particularly sunny and at first I could not spot any 'chalkies' but as I walked, they were disturbed and I realised that there were actually quite large numbers. When the sun did appear occasionally, they were much more evident.

I reached my daughter's house at Burghfield Common in time for a picnic lunch then we sat outside in the garden for the remainder of the day. On the two buddleias, there were peacocks and red admirals continually nectaring, occasionally joined by some small or large whites. A brimstone was attracted to the runner bean flowers whilst meadow brown, comma, gatekeeper and holly blue butterflies were also made an appearance from time to time. also an emperor dragonfly.. However, the butterflies that caught our attention the most were the purple hairstreaks. I saw at least 3 amongst the oak leaves, and one or two regularly flew past us as they explored other areas of the garden, settling from time time for a few seconds on the ground or on a plant. One did open its wings, but to my surprise they looked completely brown, with no purple visible. It maybe that it is quite a worn specimen and the purple scales have worn off. I did see an individual higher up in the oak which did give me a glimpse of purple, though. I decided it would be an ideal opportunity to do a Big Butterfly Count with the following results:

Peacock 8, Red admiral 2, comma 1, large white 1, small white 2, purple hairstreak 3, meadow brown 1, holly blue 1, gatekeeper 1.