new delhi the common house sparrow once part of every household is fast disappearing from urban areas including delhi ornithologists and wildlife experts speculate that the population crash could be linked to a variety of factors like lack of nesting sites in modern concrete buildings disappearing kitchen gardens increased use of pesticides in farmlands and the nonavailability of food sourcesks gopi sundar of the indian cranes and wetlands working group says although there is no concrete evidence or study to substantiate the phenomenon the population of house sparrows has definitely declined over the past few years he attributes it to a number of reasons the widespread use of chemical pesticides in farmlands has resulted in the killing of insects on which these birds depend seedeating birds like sparrows have to depend on softbodied insects to feed their young ones he saidthe other possibility could be increased predation by crows and cats said gopi sundar so while crows are growing in number as a result of unchecked garbage accumulation in the city more and more sparrows are falling prey to them he saidaccording to dr vs vijayan of the coimbatorebased salim ali centre for ornithology and natural history the avian species can still be spotted over twothirds of the worlds land surface but ironically there has been a rapid decline in the population of these onceabundant birdschanging lifestyles and architectural evolution have wreaked havoc on the birds habitat and food sources modern buildings are devoid of eaves and crannies and coupled with disappearing home gardens are playing a part in the disappearing actvijayan adds that the decline of the house sparrow is not just restricted to india in london too birdwatchers have noted it vanishing with concern buckingham palace reputed to be the richest wildlife area in central london has seen its sparrow population dwindle to zero