Walking down towards the canal I wonder what it is my daughter will remember of her first holiday. It is six o'clock in the morning and dawn is already belligerent over Cavan. Cattle are at the work of swishing flies in the fields. Swallows are promiscuous with movement above the water. An early morning barge makes its way towards Ballyconnell and a man looking as hungover as God on the eighth day raises his hand with a weary wave. My daughter lets out a little gasp of happiness and surprise.

Isabella notices all these things - she has the strange ability to turn her head almost a full circle, like a woodcock, and her curiosity is boundless.

We go down to the edge of the canal where there are dragonflies and reeds and dew on the edge of long grasses. There is a cold, fresh wind. The sun fashions wheels of light on the water. A single swallow darts and plunges through the sky - but Isabella is fascinated by none of this. Instead she has settled her intent on a row of concrete blocks that sit on the bank of the canal. Bricks. Maybe 20 of them. Sad and grey. Stacked and ugly. Forgotten and useless. Functional only for being forgotten. But right now they are perhaps all that exist in her world and she streches out her arms and squeals as if to say: Right there is my holiday.

For half an hour she sits on the blocks - she can't yet crawl - fascinated by their texture, their heft, the angles, the colours. Nothing else around her really matters. For a moment I am a bit perturbed; I want her to take in the beauty of the canal, not to sit and laugh on dirty concrete blocks. But then it strikes me that, to her, all the world's a wonder, that these concrete blocks have - as the poet says - the freshness of deep-down things. I let her loose on the bricks and for that instant I feel like the first man who ever whistled.

Whatever we are is wherever we've been. I have begun to believe that we are the simple algebra of our places. My own childhood holidays come back to me now that I've spent much of August travelling around Ireland with my wife, Allison, and six-month-old daughter.

These memories are erratic and plentiful - hanging a fishing line off the pier at Ballyvaughan, wearing elephant flares in Portsalon, playing rounders in Courtown, chipping amethyst in Achill, roaming the strand in Tramore, playing dodgems in Portrush and, most of all, childhood summers at a farm in Derry.

The farm was near Garvagh and I recall flinging dried dung through the air. I recall an old anorak that I had to turn inside out because I wore "Free State" badges. I recall crashing a tractor into a low hedgerow; my grandmother's cherry cakes; walking home with my uncle after a day in the fields; driving with cousin Seamus and being stopped by the RUC; fishing with a friend in the Agivey River; and I can still recall all the smells, the rain, the linseed oil, the fresh milk, the cowshit, the silage.

They were special days for me. I was let loose to explore whatever worlds I wanted. I think that those days affected me as profoundly as any others. Perhaps this is pure nostalgia, perhaps it is memory imagining my world for me, but summer holidays are fabulously extant for me, especially now that I am a father and my summer holidays have taken on a whole new texture. Maybe I don't even really remember these things. Maybe I have been told the stories by my own parents and so now they have become real. But no matter, imagination is even more powerful than anything real.

Of course, Isabella will remember nothing of her first holiday. It will be Allison and I who will choose to do the remembering for her.

And so we won't remember the dirty nappies and the car problems and the lost maps and the midnight crying. Instead we will remember the good moments. As a friend of mine says, paradise is not a place to live, rather it is a place to visit. The difficulties make the rest of the journey worthwhile.

In truth, holidays become different things when you're a parent. For me they have split open the world with wonder. I can see through my own eyes and through my child's.

Early that morning last week in Cavan, as my child fell asleep in my arms and we walked away from our canal-side blocks, I felt that I was living three holidays all at once - the present one, the ones in the past and the holiday that my daughter is currently living. I will tell her about it and maybe one day, just maybe, she will choose to use it as a memory - sitting on bricks.

Colum McCann is author of Fishing The Sloe-Black River; Songdogs; and This Side Of Brightness, which will be published by Phoenix House next January.