For generations, house sparrows have added child-like freshness to households with their presence. Scientists and experts say that severe changes in the urban ecosystem in recent times have had tremendous impact on the population of house sparrows whose numbers are declining constantly.

Scientists believe that the birds may never return unless some concrete steps are taken now.

They used to build their nests below tiled roofs of houses. However, changing architectural designs in urban settlements leaves no such place for them to nest.

Mobile tower radiation and excessive use of chemical fertilizers are aggravating the problem and have been identified as potent sparrow killers.