Our most common bird: the tiny wren

We once had two cats, and while one was a fat, lazy arse of a thing, the other was a sleek huntress. Maybe that had better be hunter, so as not to be sexist. Anyway, she was female, and she caught stuff. Once I saw her with a rat in her mouth – the rat was nearly as big as she was (she was deadly but dainty) – though she did not disdain mice and brought them to us as presents times without number. But her item of prey which I most remember was a wren.

She dropped it on the floor and I picked it up and gazed on it in wonder, this bird no bigger than a plum: it was freshly dead with not a mark upon it, still warm in the palm of my hand in all its mottled brown beauty. I had never been so intimately close to a wren before and I noticed with surprise how elegantly long and slim its bill was, specially designed for gleaning the minutest of insects and spiders from the leaf litter on the ground: almost a laboratory tool. A pipette, say. I was stopped in my tracks; somehow it seemed enormous, this death of a tiny bird. I had it in my mind all day.

It came back to me this week when I read a scientific paper estimating the bird populations of Britain and was reminded that the wren is the commonest of them all. Did you know that? Not the house sparrow, the starling, the blue tit or the blackbird, but the wren, Troglodytes troglodytes. According to the paper (by Musgrove et al in the current edition of British Birds), across the country there are more than 17 million wrens getting ready to breed: compare that with 13.3 million robins, 12.4 million chaffinches, 10.8 million wood pigeons and 9.6 million house sparrows.

Yet we’re not nearly so aware of them as we are of the others. The scientific name means “cave dweller” and that captures their somewhat skulking habit: they tend to hide in the garden shrubs. You hardly ever see them on feeders or bird tables or hopping around on the lawn.

But you certainly hear them. They may be traditionally our smallest bird, the one that used to appear on the farthing coin (though the goldcrest and the firecrest are even smaller) but ounce for ounce they must be the loudest, for the song and the alarm call are explosive. The song is easy to recognise, with an unfailing high-pitched trill in the middle, while the alarm call is a strident chacking, and I first knew it as a boy birdwatcher when I spent five minutes trying to spot an extraordinarily loud, scolding blackbird in a patch of woodland foliage and eventually found it wasn’t a blackbird at all.

It sounds irate, as if something has upset it. It is livid. Fuming. It even looks it. And I carried that association of anger with me from then on, thinking it my own perception only, until I came across one of the 20th century’s best poems, Robert Lowell’s 'For The Union Dead', which honours a hero of the American Civil War, Colonel Robert Gould Shaw, killed leading a regiment made up entirely of black soldiers.

His death is commemorated in one of America’s most moving public monuments, a bronze sculpture by Augustus Saint-Gaudens (“the American Rodin”) sited on the edge of the Boston Common of Shaw leading his men. Lowell’s poem, published in 1964, is a tribute to the monument and the man, and in it he says of the Colonel, who on his horse is “as lean as a compass needle”: He has an angry wrenlike vigilance

That might seem curious to some, but the instant I took in the words, I knew exactly what Lowell meant.

Angry wrens constitute anthropomorphism, of course, but lending species human characteristics is fine by me if it helps us look at the natural world more closely. Wrens may not be angry, but they certainly sound as if they are. Watch out for them, and listen, too. They’re singing now. Getting ready to nest. All 17 million.