Description: Wingspan 34-42 mm. Adults are extremely variable both in colour and markings with many named aberrations and forms. Forewing colour ranges from blackish brown through to pale grey. The stigmata and the subterminal line are more conspicuous in darker forms. Hindwings are variable in colour from whitish brown to fuscous with a small discal spot. Mid-February to late May.

World Distribution: Western Europe as far north as Sweden and Finland.

Irish Distribution: Common and widespread in southern counties but absent from west Tyrone and north Londonderry.

Ecology: A spring species encountered commonly in woodland habitats. Adults are frequently seen at light. They also visit willow Salix spp. catkins and birch Betula spp. sap. The larvae feed during May and June on a variety of trees including oak Quercus spp. and willow Salix spp. It overwinters as a pupa.

Key Identification Features:

• Small black broken line at the outer edge of the forewing
• Straight subterminal line which is usually obvious in all variations
• Small discal spot on hindwings

Distribution Map from NBN: Orthosia incerta at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Orthosia incerta at iNaturalist World Species Observations database.