This is a satellite moth, so named for the white markings on each wing, clearly shown in the photograph above. They are reckoned to resemble a planet with satellites orbiting it.
It may surprise some people, but there are various species of moth that are autumn and winter fliers, rather than summer ones. The satellite is one, the furry dark december moth another. This specimen was in pretty poor condition, having been partially trod on by library visitors. It was still feebly alive, so I took it outside - cue strange looks - and found a sunny spot to release it in. But I didn't give much for its chances.
Later on, I headed out for a somewhat limping, coughy and sneezy run. Many black headed gulls - in the hundreds - were on Balderton Lake, and a cormorant was making a rare visit to annoy the anglers. On Clay Lane, I had a typical sighting of a bullfinch, a white flash of rump flying across the path, and in the trees above there seemed to be both fieldfares and redwing, although the fading light made it hard to tell. The haw berries would be attracting them.
I eventually returned home to find the robins singing in the baby oak tree, and the blackbirds throwing the dead leaves around in every corner of the garden. The singing of the robins is a particularly cheery sound at present.