Thymelicus sylvestris
Caterpillars munch on:
And may occasionally use other grasses such as:
Adults feed on a range of flowers including:
Small Skippers spend the winter as tiny caterpillars, tucked up inside a tube of grass. Hatching from their eggs in the late summer, they barely move before spinning a silk cocoon around themselves and hibernating until the following spring.
There is even more about this species on the main Butterfly Conservation website
Male Small Skippers are territorial and will perch in a favourite spot and fly out at any passing butterfly, hoping to find a female to mate with.