Sparrows find a perch on a church grille. Ecologists say Calcutta's highrise culture has all but killed the bird. (Reuters)

Calcutta may have joined the rest of the globe in gearing to celebrate World Forest Day on Tuesday, but with each passing hour, the last vestiges of wilderness are disappearing from the city.

And it's not just nostalgia when your ears strain to hear the call of birds at dawn ' it is a human instinct to turn to nature for succour. But with each summer, the birdcalls have become fainter and the concrete facades that reflect heat tell us why.

'Did you know that we have almost killed the sparrow' They can't find nooks and crannies in the multi-storeyed buildings. It is the same with shaliks or mynahs, of which we had as many as five indigenous varieties,' said Shakti Banerjee, state director, WWF (India).

He continued: 'You can't blame the gangshaliks or bank mynahs for disappearing either ' we have hardly left any gang (the banks of a waterbody) for them. It is the same with the species of frogs we once had in Calcutta. People have hunted them mercilessly for meat and filled ponds with refuse to hasten the landfill. We have, thus, lost the kolabyang and shonabyang.'

'Like most wildlife in Calcutta, the night heron can only be found in central Calcutta and around Fort William, where at least some tree cover remains for them to nest and roost,' said Banerjee. 'We don't care about wildlife acts and don't worry if the illuminations or loudspeakers disturb the urban ecology.'

He rued: 'We get complaints of monsters and strange animals entering houses, when it is only the harmless palm civet (bham), one of the few wild mammals to have survived in the city because of its ability to climb trees and high buildings. The large Indian civet (gondhogokul), which is not as agile, is today almost extinct. There are laws against killing jackals, yet the last few khyaksiyals in Calcutta can only be found in places like Tollygunge Club, where there is some foliage.'

The state unit of WWF (India) tries to buck the trend by spreading awareness in schools and supporting NGOs working for the cause of urban ecology. 'The government has become more conscious and we have met with some success from time to time, but the public must involve itself in restoring the balance,' maintained Banerjee, pointing to the rapid depletion of wilderness on the fringes of the city.