A small geometer with a mottled, light to dark grey ground colour. There are three dark crosslines which are sometimes broken. Wingspan 30 to 35mm.
It flies May to June in one generation. Found in Birch woodland, and parks and gardens where Birch grows. A resident species, common and fairly well distributed across most of Britain, except for Ireland and Scotland where it is more localised.
The caterpillars feed mainly on Birch.
Photograph of Grey Birch (Aethalura punctulata), taken May 2014, rear garden, Staffordshire. © Pete Hillman 2014. Camera used Nikon D3200, with Sigma 105mm macro lens.