Survey indicates decline in migrant waterbird species, population in Coimbatore district

Decline in migratory waterbirds population in Coimbatore wetlands highlighted by recent Asian Waterbird Census findings.

The recently-concluded Asian Waterbird Census (AWC) in 31 wetlands in Coimbatore district has indicated a decline in the population of migratory waterbirds.

According to the Coimbatore Nature Society (CNS), which carried out the survey, a total of 9,119 birds of 149 species (migrant and resident) were recorded in the 12th edition of the exercise in the district held from January 14 to 19. The previous year’s survey had recorded 16,069 birds of 201 species.

As per the findings by the CNS, there is a worrisome decline in both migrant waterbirds species and population from 2017. While the population of the migrant waterbirds declined from 1,282 in 2017 to merely 300 in 2025, the number of migrant waterbird species declined from 20 to 12 in the same period.

Krishnampathy topped the waterbodies for being home to the maximum number of bird species (95), followed by Senkulam (72), Kolarampathy and Perur Puttuvikki (62 each). Krishnampathy also ranked top in terms of the overall population (1,212), followed by Senkulam (720) and Kolarampathy (494), said the survey report.

Barn Swallow (740) was the most populous migrant bird species, followed by Wood Sandpiper (173) and Blue-tailed bee-eater (165) while Cattle egret (473), Indian Pond-Heron (457) and House crow (427) were the top three among the resident birds, it said.

Common House Martin, Daurian Starling, Paddyfield Warbler and Small Pratincole were among notable sightings in the survey this year.

As per the survey report, declining water quality from untreated sewage, habitat degradation caused by desilting of tanks and removal of vegetation, competition for food due to increased fishing, and the loss of critical shoreline habitats for wading birds could be reasons for the declining trend this year.