Bright sulphurous yellow wings have been flitting along the forest edge these last few days.
Not many candidates.
Likely the brimstone, Gonepteryx rhamni.
It hasn’t hatched this year. It has overwintered, probably tucked into holly or ivy, possibly down in the beech litter. It’s now on its way to find buckthorn to lay its eggs.
So the butterfly isn’t just a sighting.
It’s a clue.
Images AI generated. Couldn't catch one on my iPhone.