June 26

There’s a moment in the classic Chinese martial arts films when two great warriors oppose each other, armed with swords sharp enough to sever silk.

They meet in a great clatter of cutlery and shrill whoops – and then together, as one warrior, they rise twenty feet into the air without for a second ceasing their battle. 

This scene was played out for me in the late afternoon, the sun still hot, as I sat at the end of the garden to stare across the marsh, my eyes delighting in the opportunity to focus on something further away than a screen.

Actually this was better than the films in some ways. There were three warriors involved rather than a mere two, and they were in colours far more glorious than those worn by any swordplay hero.

They were butterflies: small tortoiseshells, as I knew before I could make out the patterns of their wings, for aerial combat like this is their second favourite pastime.

You’ll find small tortoiseshells in most parks and gardens at this time of year. The males find a nice exposed perch where they bask and soak up the sun’s energy, and when another small tortoiseshell passes by, they come flying up to investigate.

When this is another male, as it usually is, the two spiral into the air together, drop down and then rise again, each seeking an advantage. When the dispute is settled, the victorious male, if he is the territory-holder, will return to his perch and hope the next intruder is female.

We think of butterflies as creatures of infinite gentleness – who breaks a butterfly upon a wheel? But they are warriors of the air, ready to rise in sky-reaching combat at any second. 

• For more, get hold of The Butterflies of Britain and Ireland by Jeremy Thomas and Richard Lewington: the butterfly book.