disappearing peacock

we are now in butterfly count fortnight, and the butterfly conservation group have reported an "alarming" drop in the number of peacock butterflies. So it was heartening that we saw 5 or 6 individuals this morning, once it had warmed up a bit. The bramble flowers on which a lot of bigger butterflies tend to feed have already come and gone this year, and the knapweed  has not quite come into flower yet so there seems to be a gap in available food for these insects. This butterfly is feeding on a species of thistle.