This metallic day-flying moth looks to have all the characteristics of a fairy longhorn, probably the green longhorn (Adela reaumurella).
The males have very long white antennae whilst the females have relatively short ones, maybe because they don’t have to do all the pheromone detection. The ladies groom nicely but the males have spiky black hairs all over their heads. I assume this one is female.
What can we tell you about Adela? No gruesome diets or horrid habits this time I’m afraid. Naturespot says the caterpillar lives in a ‘portable case’ (whatever one of those is) and feeds on Oak and Birch leaf-litter. Its unsurprising that its common around oak trees during April to June therefore – sometimes in small dancing swarms in the sunshine, which must look very pretty. There are a couple of oaks near the clearing where we’ve seem several Adela this June so that’s consistent. Looking forward to seeing you again next April / May.