In what appears to be an indicator of the quality of habitat, members of the Perur Lake Forum recently spotted two rare visitors in Kolarampathy tank, one of the less polluted water bodies in Coimbatore.

Lesser fish-eagle (Icthyophaga humilis), a resident of forest-fringed water bodies, and tufted duck (Aythya fuligula), a winter vagrant, were spotted in the tank during a monthly synchronised survey conducted by the forum.

This is the first photographic record of the sighting of tufted duck in Coimbatore city, though the bird was sighted before in Ukkadam tank in 2017, claims Prakash G., a member of the forum.

The sighting of lesser fish-eagle in the tank gains significance as the raptor, known for its ability to lift fish from the water with its curvy talons, resides in riparian forest areas and mainly feeds on freshwater fish.

Mr. Prakash and other members of the forum namely Vijaykumar Ramamoorthy, Srinivas Rav and Sureshbabu K., spotted the two birds first on February 8.

According to Mr. Prakash, they spotted an odd one among the flocks of lesser whistling duck and garganey at a distance in the tank. “Since the duck exhibited sequences of diving as feeding strategy, it was evident that it was different from dabbling ducks seen in our area. Mr. Ramamoorthy and Mr. Rav took series of photographs to confirm its identity later,” he says.

As the group resumed observation towards the northern side of the tank, they spotted a raptor perched on a tree and a Brahminy kite disturbing it by flying close in a menacing manner. Though the raptor appeared to look like a lesser fish-eagle, they were doubtful about the sighting as the raptor prefers riparian forests habitat. They took multiple photographs of the raptor, which led to its identification. Two other members of the forum namely Gajamohanraj D. and Sharang Satish also came to the tank after finishing their observation in Krishnampathi tank and took more photographs of the duck that has unique floppy crest.

“Following discussions with G. Parameswaran, president of the forum, Mr. Gajamohanraj made multiple visits to Kolarampathy on different days and took multiple photographs to establish the identity of the duck beyond doubt,” adds Mr. Prakash. He says that Rajah Jayapal, Senior Principal Scientist at Coimbatore-based Sálim Ali Centre for Ornithology and Natural History (Sacon), reviewed the photos of two birds and confirmed identities.

According to P. Balasubramanian, senior principal scientist at Sacon, sighting of lesser fish-eagle at the tank could be an indicator of improvement in the habitat, as the raptor is a resident of riparian forests like the ones at Pillur and Athikadavu.

Mr. Balasubramanian had co-authored a paper on the bird diversity of riparian forest along Bhavani river in the Nilgiri Biosphere Reserve, which mentions sighting of 20 lesser fish-eagles nesting in the riparian habitat of Bhavani river between August 2012 and July 2014.