Description: Wingspan 33-42 mm. Adults are quite variable in colour. The forewings vary from greyish white through to pale brown. The reniform stigmata are obvious and generally darker than base colour and the subterminal line is usually pale and fairly straight. Hindwings are greyish white, but this is variable depending on colour form. Darker forms tend to have a lighter hindwing colouration. There is a small discal spot and a fine dark broken line along the outer margin of the hindwing. Early March to mid-May.

World Distribution: Western Europe from Scandinavia to Portugal.

Irish Distribution: Common and widely distributed across southern counties but less frequent further north, although it has been recorded on Rathlin Island, Antrim.

Ecology: A spring species favouring wetland and marshy habitats. Adults come frequently to light and will also visit willow Salix spp. catkins and Blackthorn Prunus spinosa blossom. The larvae feed during May and June on willow Salix spp., oak Quercus spp. and Aspen Populus tremula. It overwinters as a pupa.

Key Identification Features:

• Dark-coloured stigmata
• Straight subterminal line
• Dark broken line and small discal spot on hindwing

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

iNaturalist: Orthosia gracilis at iNaturalist World Species Observations database.