Winter migratory birds - Greater Flamingo, Great White Pelican and Cotton Pygmy Goose - have been spotted in the Okhla Bird Sanctuary recently.
The visit of these birds, which had given the sanctuary a miss for the past several years, in the monsoon has taken bird watchers and ecologists by surprise.
"This is quite surprising for all of us. It indicates the drastic imbalance in the climate world over," said TK Roy, an ecologist and conservationist.
The wildlife officials say that Greater Flamingo and Great White Pelican had stopped visiting the sanctuary two years ago and Cotton Pigmy Goose stopped visiting here many years ago. These birds usually do not visit the sanctuary during summers or rainy season.
"Birds like Greater Flamingo, Great White Pelican and Cotton Pigmy Goose, which deserted the sanctuary years ago, have been spotted during scorching heat. This is a rare occurrence," said JM Banarjee, range officer, Okhla Bird Sanctuary.
The beautiful Greater Flamingo, called Bog Hans in Hindi, is found in the Indian sub-continent. About 500 birds of this species used to visit Okhla sanctuary years back. In 2010, about 20 birds of this species were last reported here. Now, about seven flamingoes are staying over.
The Great White Pelican is a large swimming species of Pelican and a resident of south Asia. It is known as 'Hawasil' in Hindi and two such birds have visited the park.
The beautiful whitish colour Cotton Pigmy Goose - mainly found in India, Bangladesh, Pakistan, Sri Lanka and Maldives – is a winter visitor to the Okhla park and it had stopped coming to the park. This month about four gooses have been spotted.