Description: Wingspan 40-45mm. Adult males are generally reddish brown, although this ground colour can vary considerably; some individuals can be much lighter or darker. From the end of September through to mid-February but more commonly encountered in late October and November, however there are occasional records, which extend beyond its normal flight period.

World Distribution: Throughout Europe and Armenia.

Irish Distribution: Widespread and frequently encountered in southern counties, scarcer further north, which may be attributed to its late flight period and limited fieldwork especially in northern counties at this time of year.

Ecology: An autumn species inhabiting woodland, bogs and a variety of other habitats. Males come frequently to light in moderate numbers. The larvae can be found from April to June on a variety of trees, particularly oak Quercus spp., birch Betula spp., willow Salix spp.., Hawthorn Crataegus monogyna and Hazel Corylus avellana. It overwinters in the egg stage.

Key Identification Features:

• No dots along the outer margin of the hind wing
• Discal spots on all wings
• Wingless females

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

iNaturalist: Erannis defoliaria at iNaturalist World Species Observations database.