Environment

Why the breeding of spot-billed pelicans at Vellalore Lake is good news

The chick reaches into the parent’s gullet for its food

The chick reaches into the parent’s gullet for its food   | Photo Credit: Special Arrangement

The pelican brief: Spot-billed pelicans have bred successfully at Vellalore Lake for two consecutive years. And that is good news, say members of the Perur Lake Forum

“Look at this.” Chetan Joshi holds out his phone to show a video of pelican chicks feeding from the parent’s gullet. G Parameswaran is also showing photos on his Macbook and waxing eloquent over the delicate colours in the breeding plumage.

The excitement is palpable as the members of the Perur Lake Forum talk about their documentation of spot-billed pelicans breeding for two years consecutively at Vellalore Lake.

These pelicans are present throughout the year in the Greater Coimbatore area but usually migrate for breeding. In January 2018 — on January 27 to be precise, says Parameswaran — the group learnt that a cluster of birds had hatched chicks. They began to record all the data they could get and resolved to get what they had missed in the next season.

Fortunately, the pelicans reassembled in the same spot and they were able to get a range of photographs, videos and screen grabs of pair bonding, nest building, copulation — “Unfortunately we couldn’t see the egg laying. That was inferred when we saw the pair sitting in the nest” — hatching, young chicks, feeding and more.

More about the pelicans
  • Local migrant species like these pelicans require large undisturbed wetlands and prey availability to raise their young. The only known currently active site in Tamil Nadu is the Koonthankulam Bird Sanctuary near Tirunelveli.
  • These birds take nearly four years to attain breeding status and their breeding season in South India lasts for six months from November to April
  • The birds are generally white but, during breeding season, the feathers on the throat and sides turn pink and a yellow patch appears on the chest
  • As they hatch the chicks and begin feeding, black spots start appearing. Slowly they go back to the basic plumage
  • Both male and female birds take turns to incubate the eggs and share the task of feeding.

Survival instincts (Clockwise from far left) A chick reaches right into the the parent’s gullet to retrieve its food; The yellow patch on the chest is part of the breeding plumage; During the nest-building phase

Survival instincts (Clockwise from far left) A chick reaches right into the the parent’s gullet to retrieve its food; The yellow patch on the chest is part of the breeding plumage; During the nest-building phase   | Photo Credit: Special Arrangement

In one photo, two chicks have stuck their heads into the parent’s gullet to feed. In another, the adult bird is delicately dropping some pre-digested food into the nest for the chick to feed on. “As the chicks grow, the nest has to be strengthened. When the adult bird brings material to refurbish the nest, the youngsters sometimes mistake it for food and grab at it. The ensuing tug of war is quite comical,” laughs Parameswaran.

Nest building activity in one cluster of spot-billed pelicans

Nest building activity in one cluster of spot-billed pelicans   | Photo Credit: Special Arrangement

Why is this event significant? Simply put, it is a sign that our wetlands are, ecologically speaking, still in decent shape. As Sai Vivek points out, the lake was dry for over 15 years and was cleaned up just two years ago. He makes a special mention of cleaning of water channels while Sharang Satish points out that the Miyawaki forests in the vicinity also helped.

Perur Lake Forum
  • PLF was formed in 2014 to collect and collate data in a scientific manner about birds seen in Coimbatore’s wetlands. “The composition and status of water birds of Perur Lake in Tamil Nadu, India” by G Parameswaran and R Shivashankar was published in the Journal of Threatened Taxa in the October 2018 issue
  • The current members are G Parameswaran, R Sivashankar, Vridhi R, Sai Vivek, Dilip Joshi, Gajamohanraj, Chetankumar Joshi, Sharang Satish, Prakash G, Richard MM, Sneha Richard and Sandeep Richard
  • The group has been monitoring birds at in Perur Lake monthly for more than five years, conducting the Anuvavi Bird count for two years and also monitoring the Krishnampathy and Kolarampathy wetlands for one year.

The talk moves to threats from poaching and fishing. “Sometimes we find the young birds in the water,” says Chetan Joshi. “So we asked one of the men in the lake. He said that it had fallen from the nest.” Vellalore lake has also been let out for fishing, points out Prakash G, and sometimes the fishermen use catapults to bring the birds down. Gajamohanraj mimics the fisherman: “I’ve paid ₹50,000 for fishing rights and you expect me to keep quiet when these birds eat up all my fish.”

There is even threat from siblings and parents. “Stronger siblings will push the weaker one out of the nest,” says Prakash and Parameswaran refers to cannibalism of the weaker chicks.

All of them are cautiously optimistic about the future. While they hope to publish a scientific paper on the data they have collected, they cannot stress enough the need to conserve our wetlands. “But it has to be done scientifically,” emphasises Parameswaran. “Human intervention and overexploitation of resources can lead to deterioration.”

Vivek rues the scooping out of lake beds to deepen the water bodies and Sharang mentions how untreated sewage continues to be let into the water.

All agree that wetlands have different functions with water storage and fishing being only two. “Once you disturb the ecological balance,” says Parameswaran, “all other functions will deteriorate.”

They hope that the fact that these pelicans have nested here successfully for two years will “get the powers to look at a long-term ecological strategy to manage wetlands.” Time only will tell.

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Printable version | Apr 2, 2020 10:30:18 PM | https://www.thehindu.com/sci-tech/energy-and-environment/why-the-breeding-of-spot-billed-pelicans-at-vellalore-lake-is-good-news/article30605799.ece

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