In as little as 15 years the migrating birds may be gone
Among them are a dozen rare or endangered species. But wildlife experts say the country does not provide a safe haven for the birds, with about half of them falling prey to poachers.
Ferruginous ducks and Baer's pochard are among the dozen or so endangered waterfowl which make the flight to Bangladesh.
The remote area seems like a winter paradise - hardly any humans or traffic and a plentiful supply of food in the clear waters. Yet numbers of the migratory birds are declining each year.
Munjurul Khan from the Bangladesh Environment Ministry says the threatened species are being taken by hunters.
"It's really a major problem for the migratory birds in our country. If you look at our study result that we found, 50% of the waterbirds are hunted each winter season. So that I mean that if 60,000 birds come to our country, 30,000 are just lost by the hunters."
Pallas's fish eagles is once such species. There are only about 500 of them left in the world and three-quarters of them are to be found in Bangladesh during the winter, arriving from the Himalayas to rest and breed.
One black-necked stork was sighted last year - the first of its species seen in five years. It lost its flock because it was injured and, after tending to its wounds, local people clipped its feathers so it could not fly away.
Growing threat
There is a strong market for the migratory waterfowl which are trapped for food.
The practice is illegal, but it is difficult to enforce the law in such a remote area.
The trappers use bamboo poles and nooses of strong but almost invisible thread. The birds get caught in the unseen nets and end up caged in street markets.
One investigator said: "We observed in the field that they're trapping vast quantities of waterfowl in different kinds of snares, nets and other traps and they're selling it for commercial purposes. Some of the species global population is a few thousand so if they trap every year, every season, that is a threat to the globally threatened birds population."
Ornithologists say bird-hunting in Bangladesh is a threat to the global survival of migratory birds because such huge numbers pass through the country during their annual migrations. Traditional subsistence hunting is being replaced by commercial trapping.
Environmentalists say overfishing is another threat to the birds. Traditional fishermen from the Koibarta community now work for businessmen who control fishing in the area.
There is still time to save the birds but the authorities must act quickly. If they do not some species may only survive another 15 years, and future generations may never witness the marvel of the migrating waterfowl.