The Orange Underwing flies around the leafless canopy of mature birch trees on sunny, still days in early spring. The moths rarely descend low enough for close inspection and are best observed through binoculars. They appear orange in flight, although as the name suggests this colour is largely restricted to the hindwings. The forewings are blackish-brown with white markings.Can be confused with the very similar Light Orange Underwing (Archiearis notha), which is found mainly in south-east…