The charm of London's sparrow substitutes

"I've had triplets," I say proudly, "two years running." The middle-aged man is clearly not impressed.

"I've got 12 myself," he says smugly.

OK, so he's trumped me. There's always a bit of one-upmanship around the bird seed bins at the local garden centre and his goldfinches outnumber mine, though I bet mine would score higher in a Sats test. Perhaps I should run after him and throw in my blue tit and great tit triplets, too, all now in an advanced stage of juvenile delinquency, but there's no need to tell him that.

Goldfinches are the new sparrows. Until five years ago I had a colony of 10 urban sparrows who hung out in the honeysuckle-Mermaid rose hedge and woke me every morning throughout the summer with their 5am squabbles. Then overnight they just upped and left, handing over my alarm call to the 747s that fly alongside my bedroom window at threeminute intervals.

No one really knows why London's sparrows have vanished, though the favoured explanation is that we've put paid to their nesting sites by overgrooming the exteriors of our houses. I certainly miss the cheeky brown birds, but the goldfinches that have moved in to fill the void are little stars in their own right.

It's not called a charm of goldfinches for nothing. With their little red and white faces and black and yellow flashes they rank as one of the prettiest of the garden birds and, thanks to a white stripe under each wing, always look as if they're turning happy cartwheels in flight.

They won't visit your garden or allotment unless you make it worth their while, though. You need a dedicated feeder, filled with niger (thistle) seeds, sited near cover. Provide a shallow container of water, too, high up where marauding cats can't pounce, and top up the seed and water all year round. (No one said the thrill of seeing goldfinches would be a cheap one.)

Watching three brown-headed babies lined up on a lilac bough alongside the feeder fluttering their wings hopefully and twittwittwittering for food while their parents ignored them and got on with their own meal was highly instructive at the weekend, and it occurred to me that it might make a useful model for the feeding of human juveniles. The pecking order is ruthlessly applied in goldfinchland, particularly to teenagers.

Of course, if you want the real lowdown on goldfinch family life - indeed on any bird life - you need a decent pair of binoculars. Just take care the neighbours don't get the wrong end of the stick.