House sparrow population is stable, says report

Ever wondered where the familiar house sparrows had gone this summer? Though the pandemic induced lockdown kept many of us indoors, the population of the house sparrows has become stable and its pervasive presence throughout Tamil Nadu and Puducherry appears to have gladdened the hearts of birdwatchers.

Even in densely populated urban areas like Chennai, these small birds, especially the grey-headed, white cheeked male with conspicuous black bib and rufous neck, and the female with buff, black and brown backed, have been sighted in several places indicating their ability to survive away from rural areas.

Currently, the population of House Sparrow (Passer domesticus), one of the most widely distributed species, is stable across India and there is no cause for immediate conservation actions, claims a recent report by the Salem Ornithological Foundation (SOF).

The report, which aims to help people understand the distribution of House Sparrows in Tamil Nadu and Puducherry, is also meant to spread awareness about the importance of citizen science initiatives like eBird.

The district-level distribution of House Sparrow appears to be very uneven due to the lack of eBirders in some of the districts. "So, there are plenty of data gaps to be filled in the eBird database.

Thus, it is evident that our state requires more sampling and a lot of contribution to eBird by bird watchers and nature enthusiasts is really necessary," says Ganeshwar S V, founder-director of SOF.

Inspired by the Australian researchers' approach of combining citizen science and big data analytics in estimating the number of wild birds in the world, the Salem Ornithological Foundation decided to create detailed distribution maps for this particular species for each of the 38 districts in Tamil Nadu and Puducherry.

"We decided to map the distribution of one of the most familiar and favourite species of many, the House Sparrow. Similar to how researchers used eBird data to estimate the number of birds, we have also used the data from eBird to create the distribution maps," the report says.

"We analysed the data obtained, mostly from our members and numerous birdwatchers from across the state and the union territory and mapped the distribution pattern," Venkatesh S, who helped to prepare the map on distribution of sparrows, told PTI.

The maps indicating the presence of the sparrows were depicted district-wise.

"These birds got their feed in urbanised cities like Chennai," he said when asked if the sparrows' population in the metro had dwindled. Coloured grids - violet, grey and white (blank) - denoted the places where the sparrows were spotted and recorded, not recorded and absence of data, respectively.

"The absence of data was because there were no birders in those places," Venkatesh said and added that the grids were drawn using QGIS software.

With the eBird India data from the past 10 years (June 2011 to May 2021), the SOF created the interactive distribution maps (presence/absence) of House Sparrow for all the 38 districts in Tamil Nadu and for Puducherry.

The maps can be zoomed in to see the presence or absence of House Sparrows along with the names of the locations. The size of each grid (in the map) is 3.3 km x 3.3 km and the total area of each grid is 10.89 square kilometres.

The purple grids indicate the presence of House Sparrows recorded from those locations while the greyish grids mean that the bird watchers have uploaded eBird checklists from those places, but House Sparrows were not recorded and the blank grids indicate the absence of data.

The distribution maps however don't reflect the population, abundance or density of House Sparrows in the region.

The SOF had roped in the expertise of Ashwin Viswanathan, research associate of Nature Conservation Foundation for guidance on data analysis and P Jeganathan, wildlife biologist and part of Tamil e-Birders Network, of the Nature Conservation Foundation, to review the report.

The SOF hopes to publish an updated report on the abundance and population trends of House Sparrow in Tamil Nadu and Puducherry in future, says Ganeshwar who prepared the report.