Alder Moth Acronicta alni
Wingspan 33-38 mm.
Thinly scattered over most of England and Wales, this subtly-marked species varies less than some of its congeners, but melanic forms do occur in places. The adults appear in May and June and are attracted to mercury vapour light.
Prior to the use of this trapping method, the species was considered quite rare, as it seldom comes to sugar or flowers. The larva when young resembles a bird dropping, but when mature is highly distinctive, being black and yellow with a number of club-like hairs.
It feeds on a number of different trees, particularly alder (Alnus glutinosa) and birch (Betula).