Migratory bird species have declined in Coimbatore wetlands as per a recent survey conducted by the Coimbatore Nature Society (CNS) in 29 wetlands in the district as part of the Asian Waterbird Census which was held from January 9 to 15
A total of 27 migratory bird species were recorded in the survey registering a decline from 31 species in 2021 and 39 in 2020. This year’s species count in wetlands was also the lowest since 2017.
The survey report compiled by Pavendhan A. said that the decline in migrant species was a “worrying factor”. The population of ducks and waders was very poor, it said.
It said that migratory birds were increasingly finding it difficult to use Coimbatore wetlands as before due to various factors.
Wetland shores are affected due to Smart City project’s construction works, which damaged the natural shorelines, were among reasons for decline in migrant and resident waders (shore birds) population.
While the residents may move between wetlands depending on the food availability and other factors to manage a crisis, the incoming migrants during September and October months, may move out to better wetlands skipping the Coimbatore wetlands, given the good monsoon and rain Tamil Nadu had especially during the second half of 2021, it said.
In terms of the bird count (bird population), migratory species registered an increase from 978 in 2021 to 1,580 in 2022, shows the surveywhich was coordinated by CNS president Selvaraj P.R.
Resident bird population in the wetlands showed a decline from 6,091 in 2021 to 5,858 this year. However, the number of resident bird species found in the waterbodies increased from 103 to 106.
Altogether, the 25 members from CNS counted 7,438 birds – 5,858 residents and 1,580 migrants of 133 species – in the survey. Of the 133 bird species, 47 were waterbirds and 86 were others.
Barn Swallow (762), Red-rumped Swallow (491), Cattle Egret (391), House Crow (278), Indian Pond Heron (259), Rose-ringed Parakeet (258) and Little Cormorant and Little Egret (252 each) were the most populous species found in the surveywhich was held from January 9 to 15.
Krishnampathy tank topped the wetlands in terms of bird variety with 88 species, followed by Selvampathy (60), Narasampathy (59) Achankulam (56), and Kolarampathy lake (54).
Krishnampathy also topped the list on the population account with 1,065 bird count followed by Selvampathy (749), Muthannankulam (522), Pallapalayam (418), and Walayar-Tamil Nadu side (330).
The average number of species found in a wetland stood at 40 with an average bird population of 256.
Migrants Blue-tailed Bee-eater, Barn Swallow, Common Sandpiper, Wood Sandpiper and Blyth’s Reed Warbler and residents such as Indian Pond Heron, Little Cormorant, Little Egret, Cattle Egret, Grey Heron, and Indian Spot-billed Duck were found well spread and seen on most of the 29 wetlands.
Knob-billed Duck, Garganey, Northern Shoveler, Northern Pintail, Watercock, Temminck’s Stint, Pin-tailed Snipe, Small Pratincole, Whiskered Tern and River Tern and Grey Wagtail were among important sightings recorded during the survey.
Booted Eagle, Eurasian Marsh Harrier, Indian Grey Hornbill, Brown Shrike, Clamorous Reed Warbler and House Martin were among important land birds sighted.
