Keep watching those back gardens … this is a White-letter hairstreak, named after the W mark on the underwings. Butterfly Conservation call it a high-priority for conservation, and it is on England’s list of most threatened species. It’s food plant is the Elm tree, and so its populations declined severely because of Dutch Elm disease. However, there are still  Elms in Huntingdonshire which support this important species, although it is not seen often. It spends most of its time high in the trees and only rarely heads down to feed on nectar.