Caterpillars munch on grasses, including:
Adults take nectar from a range of flowers including:
This species spends the winter as a caterpillar, tucked away at the base of a clump of grass during the coldest periods. When the temperature is warm enough, it crawls out to feed, eventually becoming a chrysalis in the spring and emerging as an adult a short time later.
There is even more about this species on the main Butterfly Conservation website
Unusually, instead of carefully laying and egg straight onto the leaf of a foodplant as most butterflies do, female Ringlets perch at the top of a grass stem and eject a single egg, which falls to the ground.