The local magpies know me quite well. Often as not they will greet me as I come into the garden, hopeful, no doubt, of a titbit or two. Even when I am empty-handed, which is most of the time, they happily co-inhabit wherever I happen to be, not even bothering to look up as I walk by.

But once I put on my bicycle helmet, it is another story. Even if I do so right in front of them, repeatedly, they no longer know who I am and they become very cross at my presence. Gentle warbling gives way to fierce shrieking, with neighbouring birds joining in the war cry.

No wonder cyclists get short shrift from magpies during nesting season. Not only do we approach at speed, as if by magic, but we refuse to show our faces. It's a standoff without any chance of resolution.