Impact of Urbanization on House Sparrow Distribution: A Case Study from Greater Kolkata,India

House Sparrow was the most abundant bird species near human habitat until few years back. But from the mid of twentieth century, the declining trend of House Sparrow has been reported from various countries. It has already been red listed in Netherlands and UK. Researches indicate the declining trend of House Sparrow in different cities of India like Delhi, Mumbai and Bengaluru. A 3-month wide survey has been conducted to get a preliminary idea about the distributional trend of House Sparrow in greater Kolkata. Depending on nature of urbanization and human habitat, greater Kolkata, has been subdivided into four regions (Planned City, Highly dense city, Medium dense city and Low dense city regions). In high density urban region the avian density recoded was highest, although avian diversity was maximum in medium and low dense city regions and minimum in planned city. Among 20 observational units of planned city region, House Sparrow has been noticed in 6 units and crow in all units. Among 115 observational units of rest of the regions of greater Kolkata, House Sparrow was observed in 79 units and crow in 98 units. The preliminary information revealed from this survey indicates towards negative relationship between urbanization and House Sparrow population in greater Kolkata and this negative influence is maximum in planned urban region. The presence of sufficient number of House Sparrow in any region indicates environmental stability of that region. So the declining trend of House Sparrow population in greater Kolkata, particularly in planned city region, indirectly gives the evidence of serious environmental degradation.