There is a bird in my brain. I hear it at odd hours. I wake up in the ashen dawn and hear - koo hu. It's not too loud, certainly not louder than the cawing of the waking crows, but it's insistent and cloying. Inevitably sets aflutter something deep within, something that is otherwise oblivious to itself. I turn on my side, pile the pillows over my head, shut eyes and start to browse frenetically all the dream templates at my behest before sleep loses its early morning Velcro stickiness.

A couple of hours later, I am walking in through one of the huge iron gates that open into the south Calcutta Lakes. I have forgotten the avian intrusion from some hours ago. Am about to turn on the Runkeeper app on my smartphone for effect. And just then it goes, ever so meekly - koo hu. It is the male that thus sings out, I have been told. The female only warbles.

There is safety in numbers, besides, wide awake, feeling fortified, I focus on the walk. The trees in the Lakes, the ficus this, the magnifera that, all seem invested in the fitness routine; either toe touching or bending backwards or stretching. Koo hu, I hear, this time, loud and confident.

The cuckoo is a deviant bird. Does not like to build its own nest. The call is part of the mating ritual, but oftentimes it is also to beguile other birds in whose nests it likes to lay its eggs. Brood parasitism this behaviour is called.

I keep walking. Past the self-indulgent cormorant, way behind the huffing-puffing joggers, the man doing pelvic thrusts on a purple mat, the army men at their morning drill shuffling like a column of leaves in their fatigues. Koo hu, koo hu, it calls cheekily. Experts talk about egg mimicry or how cuckoo eggs closely resemble the bird species they are prone to trick in a particular geography, making it difficult for the host bird to spot the intruder. I take out the earphones and switch on the radio, which is playing only commercials.

I keep walking. Past the young mothers who have dropped off their children to school and are now poring over blouse designs, past the cricket lessons in progress, past pot-bellied men watching the boys at the nets, their eyes wistful for a youth that has long slipped past deep square leg, past the man with the sandpaper voice chanting Shiv stotras to two canines, one black and the other snuff, a bagful of biscuits in his hands, when, outstripping all, the bird cries out - koo hu, koo hu, koo hu.

What science puts down to clinical observation, literature will make a virtue or vice of. The Fool tells the kingdom-less Lear, " The hedge-sparrow fed the cuckoo so long/That it had its head bit off by its young." The olden word "cuckold" derives from the cuckoo's tendency to mine absentias. But the song no one can fault. Heady and sweet, it connotes the fullness of love and life. Beethoven imitated it in his 6th Symphony. So did Delius and Mahler.

The first time I remember hearing the bird cry ever, I was not even as high as the grills of the verandah skirting the parents' bedroom. That onerous thing called the final exams were just over and it was the morning after. I woke up and heard - koo hu. And I remember feeling this hollow urgency in the pit of my stomach, like I had forgotten to write a whole paper. Would that be the earliest, most elemental sense of temporality? Perhaps. Is that why they have been putting cuckoos in clocks for centuries? Who can say.

That day at the Lakes, I push on past the couples, the shy ones leaning against one another, the serious ones deep in conversation, the illicit ones with furtive eyes, the filmi ones at odd angles in passionate liplock, the wedded ones expressionless. The bird now goes koo hu, koo hu, koo hu, koo hu, threatening to pierce all sanity.

I spy two greyheads - unfeathered - sitting next to each other on a solitary bench, just beyond the cricketers. The man is talking. And whatever it is that he is saying, the woman is amused, her lips are twitching. I walk right past them and up to the dead end where the white lilies stand at attention and do an about-turn. As I walk back, I see the man get up and say goodbye. The woman keeps sitting, radiant, her expression a mystery. A sparrow ploops down from the tangle of boughs before me, and so does an odd line from a poem I have read only in part: "Why were you born when the snow was falling?/ You should have come to the cuckoo's calling..."

I half expect the bird to sing out, but it doesn't. The deviant bird has a keen sense of timing.