This year, only two out of 20 species of migratory birds have come to one of their regular winter transit points in Bangladesh, the lake at Jahangirnagar University, bird watchers and ornithologists said. They blamed the decline on an alarming trend witnessed for the past five years. At least 61 species of birds used to migrate to food-rich lakes and wetlands of Bangladesh to spend the winter, abandoning lakes high in the Himalayas and from different parts of Europe and Siberia every winter. But their numbers have declined sharply due to climate change, drying up of food sources, thanks to over-fishing in the lakes and wetlands, use of pesticides during rice farming, thereby reducing the number of fish and other aquatic life, including plankton, on which the guest birds depend.
Added to these are the presence of trappers and hunters despite a ban on hunting and trapping. The number of migratory birds will fall further in the days ahead.
Professor Mostofa Firoz of the Zoology Department of Jahangirnagar University (JU) told The Independent on Saturday that the number of migratory birds has declined sharply this year. “At least 15-20 species of birds visit the JU lakes every winter, but this time only two species have landed there,” he said.
Usually the migratory birds follow three routes via Bangladesh to Sri Lanka, Via Bangladesh to Myanmar-Indonesia-Malaysia and via Bangladesh to China, he added.
“The winter has been delayed due to climate change. Besides, duration of the winter in cold-prone regions has become short because of rise in global temperatures. So, if the habitats of birds are not changed in the cold-prone regions, we won’t see any migratory birds in future,” the ornithologist said.
He further said millions of colourful and exotic birds are seen in lakes, canals, rivers and other water bodies across the country, giving a new look to the surroundings.
Habitats of birds are gradually becoming comfortable in cold-prone Himalayan regions, Siberia and Mongolia even in the winter due to rise in temperatures because of global warming. As a result, the number of migratory birds will decline further in the days to come, Prof Firoz said.
The guest birds survive on small fish, insects, snails and watery plants after arriving from colder regions. Reduction of water bodies and depletion of many species of sweet water fish in marshes and wetlands are other causes for the decline in the number of guest birds.
The adverse climate change threatens bio-diversity, agriculture, ecology and environment, reducing the number of fish, insects, birds and other aquatic life. Besides, the duration of stay of the migratory birds has been shortened as water bodies are drying up much earlier than before.
Every year, with the arrival of winter migratory birds throng parts of Bangladesh, including Jahangirnagar University, Hakaluki Haor, Hyle Haor Tangoar Beels, Nijhum Dwip, Chittagong Hill Tracts, Mirpur Zoo, Mirpur ceramic lake and Netrokona Haor.
The birds are also seen in the northern region, including the Brahmaputra basin, Teesta, Dudkumar, Dhorla, Motherganj, Narayanpur, Berubari, Jatrapur, Begumganj, Hatia, Kodalkati, Astomirchar, Nayarhat and many other small and large lakes of the area. Ducks, along with native birds, also visit the area. Lesser Whistling Teal (Chhota Sarali),Greater Whistling Teal (Bara Sarali), Cotton Pigmy Goose (Balihansh), Pochard (Bhulihansh), Darters (Snake bird), Pintail Duck, Gurgani, etc are some of the birds.
Courtesy of The Independent
