(The writer is a 3rd year BVSc & AH student. She can be reached at email@example.com)
India is a winter home for millions of birds which fly from different corners of the world to find the best ecological conditions and habitats for feeding, breeding and nourishing their young ones. Migration is a seasonal phenomenon where birds come from different areas when conditions for their breeding ground become difficult due to unfavourable weather.
Most of the species of birds have a high metabolic rate due to which they require a rich, abundant supply of food at regular intervals of time. But this situation does not always prevail at a particular area throughout the year. So, they are blessed to have a highly efficient mechanism of flying swiftly over long distances with great strength and stamina. The speed depends upon the species of the bird and the terrains covered by them.
Each year, during winter, Assam get an influx of millions of migratory birds from different parts and corners of the world. Brahmaputra river bodies and its tributaries play host to the migrating birds because of their beautiful locations and terrains. Over 300 species of birds take shelter in the edges of the river making it a site seeing for tourists and other visitors. The birds migrate from winter-hit regions of Europe, Antartica, North America, Russia, Ladakh, Siberia, etc. Various types of water birds like Grey leg goose, Ruddy Shelduck, Crested Pochard, Common Teal, Indian Tern, Spot Billed Duck, Tufted Pochard, Large Egret, Paintail Duck, Indian Spotbilled Duck, Green Sandpiper, etc are seen visiting the river banks of the Brahmaputra.
Some kind of predator birds like Palla’s fish eagle, Hen harrier, Amur Falcon, Eastern Imperial eagle, Grey headed fish eagle are seen fluttering in the sky and residing in the trees during winter near the Brahmaputra. Reports have also revealed that some kind of endangered birds like Oriental Darter, Marbled teal are seen residing in the river. Conservation and awareness programmes must be established for conservation of such kinds of rare birds.
Year after year the population of bird migrating to the Brahmaputra river has been declining due to indiscriminate fishing and uncontrolled agricultural activities in the edges of the Brahmaputra. Such activities have disturbed the natural habitats of birds. Reports showed that there is absence of Ruddy Shelduck in Bogibeel Bridge catchment areas in Dhemaji.
The turbidity of the river has risen which compelled the birds to change their habitat. Hunting of birds has been increased in this areas due to which the ducks which used to take shelter in the Togani river, a tributary of the Brahmaputra, have declined. Even the water level of the Brahmaputra has gone down drastically which is the major reason for decline in the population of migratory birds.
Hundreds of winged visitors are also seen taking shelter in the Kaziranga National Park during the winter months of October and November. Flocks of Barheded Geese, Grey legged geese, Whistling teals etc which come from Siberia are spotted in the park. Rare birds like storks and cranes are seen wintering in the area. The parks also host a variety of raptors. But the rate of migration has decreased due to forest fire, hunting and various other activities which have to be looked after.
Deepor Beel, a place of natural beauty, located in Guwahati is home to rich variety of migratory bird species. Part of the beel is declared has a bird sanctuary in 1989. During the winter months, a large concentration of aquatic birds is seen in the beel. As reports from ornithologists, out of 219 species of birds recorded, 70 are of migratory birds. They are Siberian Crane, Barn Swallow, Asian Open Billed Storks, Pied Wagtails, Yellow Wagtails and several varieties of duck and other birds. Some globally threatened birds like Spot Billed Pelican, Lesser and Greater Adjutant Stork and Baer’s Pochard are also spotted. But birds get disturbed at the end of December due to heavy fishing for feast of the New Year and Magh Bihu in mid-January.
Jatinga, commonly known as ‘Valley of Death for Birds’, is a small village located in Dima Hasao district of Assam. The place is known for its scenic beauty with mountains surrounding it. But a mysterious phenomenon is seen for last 100 years which have attracted the eyes of many scientists. The birds commit mass suicide in this area which has become an annual event. Not only the migratory birds, but local birds are also seen doing the same phenomenon. Reports have shown about 44 species of birds committing suicide in Jatinga in the late winter months between September and November. As soon as the sun sets, hundreds of birds descend to the village, fly full speed towards building and trees crashing to their death. Seeing the lights and torches in the cities, the birds become disoriented and some of them plunge to the light post while some perch on the bushes and trees. Considering it to be the spirits, the villagers hunt them with catapults. Scientifically, actually the birds do not commit suicide but they get caught in the fog and mist, get disoriented and descend down. Despite the danger and repeated mysterious phenomenon every year, birds continue to fly in this small area covering 1500 metres.
The Wildlife and Bird Society as well as Government of Assam has taken measures to educate the village people to stop mass killing of birds. Since then, the death of birds has been decreased by 40%. Veterinarians have seen that migratory birds also play a significant role in the transmission of zoonoses. They can transfer micro organism across the globe and plays a significant role in the ecology and circulation of pathogenic organism. They act as mechanical and biological carriers and as host and carrier of infected ectoparasite. They can cause water borne, insect borne as well as tick borne diseases. They also spread Avian Influenza virus.
Migratory birds have a major role in the ecosystem. They serve key function in the inter-connected system that keep nature healthy, include pollination and seed dispersal of crops for human and livestock consumption, pest regulation and all aesthetic culture across the globe. Viewing all the reports suggested by various scientists and ornithologists, it has become very essential to conserve the migratory birds in Assam. So, recently a plan has been drawn by the Government as ‘Migratory Bird Conservation Plan’. It includes 3 areas of Assam. First is the world’s largest inhabited riverine island of Majuli, second is the three tanks built by Ahom king between 17 and 18 century in Sivsagar, and third is the Panidihing Wildlife Sanctuary. This three lies under the Central Asian flyway action plan which is among the 40 wetlands which the Centre has identified for special conservation measures of migratory birds. Under this plan, the Centre has identified 20 species of birds that take migratory routes over these areas.
Each year the World Migratory Bird Day is celebrated biannually on 2nd Saturday of May and October. This day is observed by organizing awareness campaign highlighting the needs for the conservation of migratory birds and their habitats. This year it falls on 9th of May 2020. This is a prime duty for the Government of Assam and each and every veterinarian to protect and look after those migrants which visit our state.