Feral, that’s what they are. That means they’re ours, and yet not ours. Their ancestors, the rock doves, are still around, mostly on sea cliffs but also inland. Unlike true wild species of birds their colours cover a dazzling range, like us: ‘feral form varies from pure white to almost black and includes plumages that are various shades of grey and brown’. (RSPB handbook of British birds.) The two kinds interbreed so that their chief distinguishing characteristic is nominal: one is a pigeon, the other a dove. The only other pigeon is the wood pigeon, also a pest. Other species are all doves, stock dove, turtle dove, collared dove.

We had a volunteer at PDR (Putting Down Roots, St Mungo’s gardening project) who inisted on feeding the pigeons in the parks where we worked. Jacqui would not be stopped. Sometimes she brought seed she had bought for them, more often it was bags of stale bread. But it was she who made me see that we cannot simply write them off, they are somehow our responsibility, because they are the descendants of birds kept in dovecots and rooftops to provide meat and manure, and also used for racing and messaging, because of their unerring abiity to return home. Birds which now don’t really have a home, like illegal immigrants.

How they breed and how they crowd and swarm, diseased and often crippled. How resilient and adaptable they are, having swapped their native cliffs first for the dovecots of domestication and then for the streets and cliffs of the city.

Some children are also described as feral: ours yet wild. Some dogs and cats too. These creatures who are neither one thing nor the other are a threat to established order. Yet some creatures which have a particularly close relationship with human beings are admired, like the storks which have adopted certain villages (and no others) in Greece or Spain. Or like sparrows, though they tend or used to tend more to the swarming, scavenging, noisy kind and it was only when they began to disappear that we found that we had been quite fond of them all along. But not only were sparrows seen to behave like people but people, notably the cockney sparrows, were described as birds. I read somewhere that sparrows are the only bird that only live in close association with people. They hang out in bushes and fields and gardens but they only nest in buildings. You will never see a sparrow more than half a mile from a human settlement.

The sparrows disappeared from St John’s, Waterloo, years ago, when they disappeared from most of London. Then last year they returned, shy and in very small groups at first, but this year boder, noisier and numerous, and competing patiently, persistently with the pigeons at the bird feeders. Then a few weeks ago they disappeared again, overnight as far as we know.

And it was soon after that that I met the pigeon on its nest. I was trying to restrain and prune the campsis, aka trumpet vine, a big and beautiful climber that grows on the railings of the churchyard on the Waterloo road side. It insists on growing out over the pavement and although the pavement is very wide it’s still seen as anti-social, like the pigeons I suppose. It also needs taming for its own good, because otherwise people just break off the ends of the shoots, and we lose the flowers because they only grow on the tips of the side shoots. So anyway, I was up a ladder, working at a tangle, and suddenly there was the pigeon, just inches away from me. We were literally eye to eye. It didn’t move, just stared. I had a glimpse of one white egg. Meeting a pigeon like that, so intimately, is very different from encountering the usual flock, the crowd, the mob. Then I thought, this is our bio-diversity. They go on about bats and stag beatles, rare, endangered, hanging on here and there, and how we must provide for them and encourage them. We’re concerned about the bees, and the hedgehogs, the newts, the frogs, the toads, the butterflies and moths (not the clothes moths, naturally: are they another thing that has adopted us and only us?), and talk of bio-diversity always leaves out the pigeons and the rats and mice. We want bio-diversity on our terms, which is a contradiction in terms. There’s a new plan to control the grey squirrel by lacing their food with contraceptives. And watch out, ruddy duck! It became established after escaping from wildfowl collections, and the RSPB says ‘because of the attraction of the Ruddy Duck to the White Headed Duck and because the Ruddy Duck is a dominating species, it is feared that it is capable of exterminating White Headed Ducks in western Europe unless its expansion is curbed’. It’s like the white man’s burden; we’re in charge, we have tough decisions and difficult choices to make. Nature is quite irresponsible. It’s the same with gardening.

So then I thought, the sparrows have gone again, do we just have to learn to live with the pigeons? Maybe we should build a huge dovecot in the churchyard and start eating them again. Humans are very good at controlling the numbers of birds and animals by eating them. And we could use the manure. We could even send each other messages. Then they could become doves again, like they were for Noah all that time ago.

A baby pigeon is called a squab.

But then, the other day in the churchyard, above the generalised urban roar – I was wearing my hearing aids – I thought I heard a cheep in the bushes, and it was a sparrow! I looked and saw one dash from one shrub to the next, and then another one. There were only two or three, but maybe more will return. Where have they been? There every day, all day, so fixed in their habits, then suddenly gone. And now?

Recently I have enjoyed watching a mouse from the kitchen window, running to and fro. Just one mouse. One mouse is so sweet, its tail so long. Happy now the cat is dead. Just don’t come into the house, I said.