Santragachhi Jheel, part of which is covered with hyacinth and filth. Picture by Anup Bhattacharya
The forest department’s move to start cleaning Santragachhi Jheel from next week comes a little late and may drive away early migratory birds, experts fear.
Local migratory birds like White Wagtail, Yellow Wagtail and Common Moorhen — which come from the interiors of Bengal or from the foothills of the Himalayas — start arriving in end-September.
The trans-Himalayan birds come from mid-October.
A proper cleaning of the water body — spread across 98 bighas or 33 acres — usually takes a month. But this time the duration may be little less because the forest department had cleared a portion of the lake in June.
“The water hyacinths should ideally be cleaned from the middle of August so that the lake is ready to receive the migratory guests from end-September,” said Shubhankar Patra, a bird watcher. “Birds do not like disturbances. If the cleaning continues for the rest of the month, the early guests will fly to some other place.”
Another birder said: “Birds transmit message among themselves. If the first birds see the place is not yet ready for them, they will communicate it to others. Once the message gets transmitted, many birds will avoid the lake.”
There is also a risk of outbreak of avian flu if the birds fly to some other winter destinations. “If the migratory birds carrying flu germs land in small ponds in villages and mix with local birds, there is a danger of outbreak of the disease,” said an expert.
Every year about 10,000 birds arrive at the lake during winter. About 98 per cent of them are Lesser Whistling Ducks, which come from various parts of the subcontinent.
Among the trans-Himalayan birds that come to Santragachhi Jheel are Gadwall, Garganey and Common Teal. “These birds come from countries that become extremely cold during winter,” said Patra.
The forest department has to clear the water hyacinths and dump them on select sections in the water body to create resting islands for the birds. “Building an island of water hyacinth takes time. The water hyacinths have to be dumped and bamboo poles erected around them so they do not float away. The islands must be static,” said a birder.