The curious case of missing sparrows

House sparrows, as ubiquitous as they were once upon a time, have gone ‘missing’ in our towns and cities. For the grown-ups, it has been part of the daily chores to have it heard or seen in and around the household. Yet, as one grew up, they have suddenly disappeared from the household and our neighbourhoods.

The bird’s scientific name (Passer domesticus) and common name (house sparrow) refers to its association with humans. The Latin word passer, like the English word “sparrow”, is a term for small active birds, coming from a root word referring to speed. The Latin word domesticus means “belonging to the house”, and the common name is a reference to its association with humans. House sparrows are perhaps the first wild birds to be associated closely with human beings without being domesticated.

Scientifically, it is rather difficult to assert what has happened to them for a simple fact that there is no systematic study documenting their presence/absence in different localities. For serious researchers and ecologists, urban ecology is a relatively new domain in India.

A notable effort in this direction is the ‘Citizen Sparrow’, a citizen science initiative launched in 2012. ‘Citizen Sparrow’ is an ongoing citizen science project in which members of the public are encouraged to contribute information on presence and absence of the house sparrow. It is organised by Bombay Natural History Society and Ministry of Environment and Forests (India) in partnership with the National Centre for Biological Sciences and Nature Conservation Foundation.

The effort resulted in gathering 11,170 observations from 5,939 persons at 8,802 locations across India (Citizen Sparrow, 2015: http://www.citizensparrow.in). Based on this, they have presented a summary of results: “Based on over 10,000 reports from across the country and from different years, some patterns are clear. Sparrow occurrence is reported to be lower at present than in the past, and this is consistent across the country.

Sparrow occurrence is lower in cities compared to towns and villages, and this is again consistent in different parts of the country. Still, there is a large variation in the occurrence of sparrows from city to city. For example, sparrows are reported to be widespread in Mumbai and Coimbatore, but are missing in most localities in Bengaluru and Chennai, while Delhi is intermediate.”

There is a popular perception that radiation from mobile towers are affecting these birds. From the available published literature, there is possibly only one study that suggests possible effects of long-term exposure to low-intensity electromagnetic radiation from mobile phone (GSM) base stations on the number of house sparrows during the breeding season. This has been carried out in six residential districts of Belgium. Although, there have been speculations on this front, conclusive studies are required to ascertain the effects of electromagnetic radiation.

At the outset, if there were any radiation effects, this would have affected other taxa too and it is very unlikely that this would single out house sparrows alone. The concern on house sparrows has been on the rise, mostly in urban areas, while the causes for their decline in and around human settlements are still undetermined.

What next?

Given that house sparrows are perhaps the first wild birds to be closely associated with human settlements; their declining populations may have a lot to convey about the quality of urban environment, something that we need to know. On this note, we are only speculating the possible decline, although not conclusive at this point of time. Some recent initiatives like the Citizen Sparrow can perhaps throw more conclusive light on the distribution of house sparrows in the sub-continent. You can contribute your observations by posting them on Citizen Sparrow portal (www.citizensparrow.in). With this, hopefully we will know where all the sparrows have gone!

(The author is with Gubbi Labs, a Bengaluru-based research collective)