Raiganj: Forest officers in North Dinajpur said on Monday that the number of migratory birds at the Kulik Bird Sanctuary near here had increased this year.

"This year, over 96,000 birds of different species were found at the sanctuary during a count. That means, over 7,000 more birds came to Kulik compared to last year," said Diparna Dutta, the divisional forest officer of Raiganj.

The counting had started from October 12 and concluded on Monday.

The sanctuary is spread over acres where migratory birds fly here from different countries of south-east Asia in April and May. They stay here, lay eggs and as their fledglings start to fly, they start leaving from December, said the forester.

During this year's count, the total number of birds found in the sanctuary was 96,945. Among them are open-billed stork (65,935), cormorant (9,957), night heron (10,262) and little egret (10,791), forest department sources said.

Back in 2010, the number of birds had touched the one lakh mark in the sanctuary. But due to noise pollution and some other reasons, the number declined to half the following year.

Forest officers, perturbed over the decline, consulted with ornithologists who came up with some suggestions as to how the sanctuary could be conserved in a better manner and how pollution could be checked.

"The numbers have started increasing in the past three-four years as we worked on some of the recommendations," Dutta said.

This year, the reason for the rise in the avian population, he said, was that the sanctuary could be protected from floods.

Even though the Kulik river that skirts the sanctuary flooded several localities, the sanctuary remained unaffected.

To prevent flooding of the sanctuary, the embankment of the river was heightened to prevent spillover of the water. Also, a canal that flows through it was cleaned to ensure free flow of water.

"Waterlogging in the sanctuary would have affected the birds. The eggs would have got damaged and the birds would not have found insects and other food on the ground. Also, some of these bird species live on the ground and also on tree branches. In case of flood, many birds would have also died," said an expert.

The divisional forest officer said the birds could get a safe and conducive ambience at the sanctuary. "This is why their numbers have increased. Next year, we expect the count will cross one lakh," said Dutta.