Nowadays people seldom see sparrows that once thrived in large numbers in the city and rural areas of Nepal. Their population has diminished over the years. 

Environmentalists blame the decrease in sparrow (Passer domesticus) population to industrialisation, human lifestyle changes and, most significantly, climate change.

“Traditional houses had enough space in roofs for sparrows to build their nests and roost. Modern brick and cement concrete houses do not have roofs congenial for sparrows. So, the sparrow population is thinning,” Bahadur Singh Mahara, an environment expert, says. 

Increase in summer temperature is another factor. Mean temperatures in Tarai districts, including Kanchanpur, have gone up.

Thatched roofs warm up during the summer and make the surroundings unfriendly for sparrows to make nests and reside. Excessive heat also spoils sparrow eggs. Many sparrows succumb to excessive heat.

All these factors threaten the existence of the sparrow, one of the most common birds on the sub-continent. This is grim the reality today. The tiny brown bird is on the verge of disappearing from Kanchanpur and surrounding areas, Mahara says.

He says increasing sound, air and soil pollution contribute to the disappearance of sparrows. 

“Rampant use of pesticides and fertilisers on crops is also one of the causes of the diminishing number of sparrows since the sparrow’s diet comprises small insects that pesticides kill. The grains on which the sparrows feed on also have traces of the pesticides. This has also contributed to the diminishing number of sparrows,” Mahara says.

According to him, sparrows have also started dying after feeding on the insects and grasshoppers that have perished after the farmers spray insecticides. 

Local bird watchers say they saw flock of sparrows often in the years gone by, but these days they are rare.

“The water in the streams is also polluted as the industrial effluent that is directly released in these streams and drains. The sparrows drink the polluted water from these streams and drains, and die,” said Tek Bahadur Hamal, a local. 

Another cause for the decreasing number of sparrow is streetlights, and cellphone reception towers that emit radio waves. Sparrows cannot distinguish day and night due to the street light and lose direction from the radio waves that emanate from cellphone towers.

A sparrow’s lifespan is three to 13 years. Human activity, arguably, will further diminish its lifespan. The sparrow is not yet an endangered species, but its diminishing population in south Asia should worry experts and ornithologists.