Migratory birds have started flocking in large numbers to Maithon dam, Tenughat dam, Garga, Chandrapura and other water reservoirs here much to the delight of bird watchers of Dhanbad, Bokaro, Maithon, Chandrapura, Tenughat and other parts of the coal belt. Starling, Ruff, Black-winged stilt, Common teal, Greenshank, white and yellow Wagtail, Northern Pintail, Gargney, Common coot, Mallard, Pygmy goose, Pochard, Red crested pochard and Combed duck can be sighted in these water reservoirs. Though not too many visitors arrived last year, many have started entering the zone in large numbers this December. According to Dhanbad district forest officer Sanjiv Kumar, these migratory birds start flocking to Jharkhand from November. Though they were delayed this year, due to late monsoon and rising pollution, the birds arrived as soon as temperatures dipped. Flying at high altitude to acclimatise themselves with the changing atmosphere, these migratory birds arrive from colder climates in search of food and safety. They stay in Jharkhand for at least four months till April, explained the forest officer. Tenughat water reservoir of Bokaro is a favourite haunt of bird lovers who had been disappointed last year as the few migratory birds that arrived stayed for a very short period of time. Jagdish Mahto, who works at Tenughat dam, said: