For some years, Vairamani, an otherwise tranquil, uninhabited islet in Idukki wildlife sanctuary, has been waking up to a springtime of happy activity.
It isn’t the tourists but special winged visitors who are holidaying in its sandbanks formed by the receding waters of the reservoir. Vairamani, one of the big islets in the sanctuary, has a large population of Indian river terns (Sterna aurantia), a species that lays eggs on the freshwater sandbanks and breeds them if not disturbed by humans.
River tern is easily identified with its black cap, yellow bill and reddish legs.
According to ornithologist R. Sugathan, the arrival of river tern reflects the changes in the habitat pattern of the area after the reservoir was formed in the sanctuary.
Return by May
In March now, the river tern has started laying eggs. By May, they will fly away.
River tern is known for colonial nesting and the eggs, in greenish-grey colour, are difficult to be traced in the sands.
They lay eggs near the ebbed water bodies and at times, in the creeks of roots of deadwoods.
River tern lays eggs with Pratincole and other terns, who are also increasingly making Vairamani their holiday home.
In a colony of nests, there are hundreds of eggs with three or four in each one spread over the wide area of the islet.
Suitable spot
Vairamani, of all the places in the sanctuary, seems to be the hottest spot with the islet having all the congenial features to attract the birds.
For one, it is known only to the officials of the Idukki Wildlife Sanctuary, who keep a keen watch on the breeding of the birds.
Then, changes in habitats elsewhere could be bringing more birds to the spot, which is practically isolated from mainland activity.
Fish stock
The open grasslands in the islet house reptiles and mammals, attracting raptors and igrets. The lake, with its stock of fish may also be an attraction, Mr. Sugathan said.
“The increase in the number of migratory birds is a very positive change and some surveys pointed that they are mainly from the Himalayas and Siberia,” Idukki Wildlife Warden P.R. Suresh said. An elaborate survey will be held soon to identify the new birds, he added.
As per the earlier records, there were 201 bird species inside the sanctuary. Now it has been updated to 240. The new survey is being done after a gap of nearly four years.
