With an escalating human population, due to high rates of migration from rural to urban areas, cities around the world are becoming very populated and polluted. This influx of people in urban areas has led to an overall reduction in green cover as natural spaces are converted into residential areas to accommodate the masses. This is a major issue, especially in developing countries like India where migration from the rural to the urban is very high. According to the United Nations estimation, by the year 2031, the population of Indian cities will increase by 600 million (Nagendra et al., 2013). Rapid urbanisation can be seen in major cities like Delhi, Mumbai and Kolkata where a sizeable proportion of the population come from other parts of the country. In these megacities, the condition of the environment is poor as many wetlands and natural spaces have been traded for housing societies, malls and roads. The quality of air and water in these cities is pathetic, adversely affecting the lives of many floral and faunal species that exist in these cities. Also, many native species have lost their habitat due to the intensive introduction and proliferation of non-native species in urban areas. Native avifaunal species have been one of the worst affected as they utilize the green spaces of cities for nesting and breeding (McKinney, 2002).
The House Sparrow (Passer domestics) belongs to the family Passeridae, and is one of the most widespread and abundant species in the world (Paul, 2015). The species is also known for its non-migratory status and close association with human-dominated landscapes. House Sparrows are an important indicator of the health of urban ecosystems as they maintain the ecological balance in the urban food chain, while also playing a vital role in the pollination of plants. Once a very common species in Indian cities, the House Sparrow is now disappearing throughout much of its range due to the unavailability of food and fragmentation of habitat. Many researchers have reported that the population of the species is on a decline in most major cities of India (One World South Asia, 2012). According to a report by the Indian Council of Agricultural Research (ICAR), the population of the species has declined by 80% in the state of Andhra Pradesh, and 20% each in the states of Kerala, Gujarat and Rajasthan (Kumar et al., 2018). Due to their declining numbers in urban areas, the IUCN, in 2002, included the House Sparrow in its Red Data List of threatened species (Dandapat et al., 2010).
There are numerous factors leading to the declining population of the House Sparrow in Indian cities. Factors such as lack of suitable nesting spaces in buildings; excessive use of pesticides in the production of food grains that birds consume; intensive introduction of exotics species that are detrimental to insects on which sparrows feed; reduction in overall tree cover; and high levels of pollution in cities may be responsible for the decline in Sparrow numbers. These factors raise concerns over the future of House Sparrows in Indian cities, and it is perhaps important to make efforts to conserve this species. Some basic steps that could be taken to help sparrow populations bounce back include minimal usage of insecticides and pesticides in the production of food grains, installation of birdhouses or artificial nests in homes and office spaces for nesting, and also the placing of water bowls in balconies and rooftops, especially during the summer season. Being an indicator of environmental health, Sparrows are vital to the ecosystem, and it is therefore important to protect them lest they become extinct.
- Dandapat, A., Banerjee, D., & Chakraborty, D. (2010). The case of the disappearing House Sparrow. Veterinary World, 3(2): 97-100.
- Disappearing sparrows: Common bird goes uncommon (2012), One World South Asia.(http://southasia.oneworld.net/todaysheadlines/disappearing-sparrow-common-bird-goes-uncommon)
- McKinney, M.L. (2002). Urbanization, Biodiversity and Conservation. BioScience 52(10): 883-890.
- Nagendra, H., Sudhira, H.S., Katti, M., Schewenius, M. (2013). Sub-regional Assessment of India: Effects of Urbanization on Land Use, Biodiversity and Ecosystem Services. Urbanization, Biodiversity and Ecosystem Services: Challenges and Opportunities. Springer, Dordrecht.
- Paul, M.R. (2015). A review of house sparrow population decline in India. Asia Pacific Journal of Research, 1(29): 38-40.