On a mild autumn day I might catch a red admiral butterfly taking the last of summer’s nectar, basking in sunshine or flying among the rooftops against a brilliant blue sky. I keep a mental log of my last butterfly sighting of the year, which soon becomes my first butterfly of the new year. Both are always a red admiral.

It wasn’t very long ago that the red admiral was strictly a migrant species here, arriving from continental Europe and North Africa in spring, and leaving again in autumn, our winters too cold for them to survive. Now, owing to climate change, some stay for winter instead of migrating south.

They don’t seem to hibernate in the same way as other butterflies, such as the small tortoiseshell and peacock, which enter a more consistent dormant state. So it’s common to see them on mild, sunny days, delighting those of us looking for a glimpse of spring.