Butterfly season: 2023 report

Bill Symonds finds butterfly season unusually compressed by the cold spring weather

As winter passed without any significant winter storms, I was hopeful of favourable April and May conditions for butterflies. Sadly that was not to be the case as winds remained pegged in the north and east, suppressing temperatures for the early part of the butterfly season.

Still, there were breaks in the weather here and there, but they were few and far between, making planning when in the week would be suitable to do a transect in April and early May very challenging.

The weather has really made the butterfly season so far feel very compressed. From hardly seeing anything except Brimstones (and lots of them) on transects and while out and about in April and early May, the season kicked off in the second week in May.

Transects were soon recording good numbers of the wood’s rarities such as Pearl-bordered and Marsh Fritillary with the former showing up throughout the wood. I found one worn Duke of Burgundy in Richwellstead Copse in the north of the wood and on 27th May this species was also recorded on South transect.

But then as quickly as it had begun it was over. I did North and South transects on 4th June and recorded only 2 species.Pearl-bordered Fritillary were still being seen in Eastern Clearing until 7th June.

Away from Bentley, while I was doing transects, an Orange Tip chrysalis which I had recovered to my house from a nearby hedge emerged on 21st April just before a sustained period where the daytime temperatures barely broke into double figures. Clearly it hadn’t got the weather forecast!

As I missed the opportunity to film its emergence, I had to make do with photographing one (pictured below) I’d found roosting on one of the butterfly’s larval food plants, Garlic Mustard. It was the first time I had ever seen this, round here adults usually seem to roost on Cow Parsley.

And the chrysalis this Orange-Tip emerged from…