Anandha Lekshmi and Ankita Roy, Ahmedabad: A sparrow is to a city like a tiger is to a forest. Sparrows are the bio-indicators of an urban environment, much like the tiger whose decline indicates a threat to the ecosystem. But there has been a long-term decline in the population of sparrows, particularly in urban and suburban environments. Today, on World Sparrow Day which is celebrated  to raise awareness on the importance and conservation of the humble house sparrow and of threats to their populations, we bring to you 5 reasons on why the sparrows are being gradually wiped out from the urban jungle we are creating.

Cell Phone Radiation
The electromagnetic radiation emerging from mobile towers in urban and rural areas is affecting the breeding of sparrows. In presence of electromagnetic radiation, the eggs of sparrows either fail to hatch or take longer time to hatch like a month, though their normal incubation period ranged from 10 -12 days. These harmful waves damage the immune and nervous system of sparrows, affecting their navigating sensors.

Felling of Trees
Due to urbanization trees have been felled in many parts, destroying the natural habitat of the animals. There were times when house sparrows were seen very commonly in the cities. Due to the growth of the concrete jungle, the population of these birds has declined in the cities.

Lack of food
Extensive use of pesticides and insecticides in farms and gardens is killing the bird’s primary food source: insects.  Sparrows need a diet of insects and worms like caterpillars that serve as a protein supplement, particularly during growing up phase of their life.  Non-availability of tiny insects as food affects the natural diet of the sparrows. Due to the loss of vegetation around our modern buildings and lack of native plants like adulsa and mehndi are also reasons that are attributed to the depleting population of sparrows. “One of the major reasons for steep decline that causes the deaths of these birds is the use of pesticides in the gardens. Since they are insectivores they eat insects so even a small amount of pesticide will have a lot of effects on the fragile body of the bird.” says Sherwin Everett, who works at Jivdaya Charitable Trust, an NGO dedicated to treat owner-less and injured /sick animals and birds in the city. 

Air pollution
With global warming on the rise and greenhouse gasses emissions increasing, air pollution has become severe in many parts of the world. As a result, there are many damaging molecules prevalent in the city air. Urban sparrows suffer high levels of free-radical damage but they are unable to fight it because their natural defences have a lower capacity to do so.

Widespread use of concrete
Architectural evolution has wreaked havoc on the bird's habitat and food sources. The sparrows used to build nests in the crevices of traditional houses. Now the houses have gone concrete and they leave no room for nesting sites for house sparrows, as they need entry and exit points for nestlings and not any hole will do.

So what can be done for the conservation of the humble house sparrows? Sherwin tells us, "Here in Ahmedabad we don’t have much forest cover or trees left in city areas so even putting up sparrow houses won’t be that successful unless there are sparrows in your area. But there are certain points that need to be kept in mind if you plan to put up sparrow houses, like you need to make sure that the sparrow house is water proof and can stay put in any weather, the opening of the nest should of a size that no other bird can get in but only the sparrows because large birds like crows could get in bigger openings and attack babies or eat them up. It shouldn’t be too close to a tree too, since cats can easily climb up and get to the nest. To encourage sparrows, we can put out bird feeders, water bowls, etc as it is summer now. Give the birds space to nest instead of cornering them to live in one small area and avoid the use of pesticides in the garden, lawns"