This butterfly was out and about in early March in Poitou-Charentes.
I photographed this one whilst walking along a cliff top path near Saint Palais sur Mer on 4th March 2015.
The caterpillars feed on various grasses, and are long green and thin thus resembling a blade of grass and this helps them to avoid be eaten by hungry birds and lizards.
There are normally several broods of butterflies each year. This species overwinters as a caterpillar or as the chrysalid.
This photo is from a web site called http://www.bugsandweeds.co.uk/butterflies.html