Eddie and I were sitting out on the marsh an hour or so before dusk when we heard the cuckoo again. Good. He – only a male cuckoo says cuckoo – has been hard at it for six weeks now. Cuckoos love this spot, one that we in Norfolk, without a trace of irony, call a valley: wet, reed-fringed with a generous flood-plain. 

Cuckoo! A simple, far carrying call, and for a good reason. He’s trying to summon a female from a colossal distance. In my new book, On the Marsh, I compare the cuckoo’s song to a scene in Fellini’s Amarcord, in which the main character’s mad uncle, let out for the day, climbs a high tree and shouts again and again: voglio una donna! I want a woman!

The cuckoo is all sound. So much so that on the rare occasions you actually see one, it comes as a mild shock: like seeing a piece of music rather than hearing it. The shape, with wings so sharp they seem to cut the air around it, never seems an easy thing for the landscape to cope with.

How can it be possible to see a cuckoo? Its very name is a sound, the bird exists as a noise, not a visual experience. It’s a bit like the phenomenon known as synaesthesia, when people hear colours or see sounds: the senses confused and conflated, sometimes thrillingly. Some people experience that on acid trips, but some do in real life, seeing a distinct colour for each day of the week, each number and each letter.

There are many examples of synaesthetes in all the arts: Nabakov, Kandinsky, Mondrian, Scriabin and Hockney. For my money the best of them all is Messiaen, who created landscapes with music and then filled them with birds. He referred to himself not as musician but as an ornithologist and rhythmician. 

The cuckoo kept on cuckooing above the marsh: not one to give up easily. He had been lucky as least twice, for we have heard the clear, wild bubbling sounds of a female, responding to the cuckoo’s treetop entreaty.

In the growing dark a sedge warbler sang an accompaniment. What colour was his song, do you think?