Changing patterns of birds' migration  

Migratory birds have started flying into Bangladesh and the other warmer countries in South Asia. It has been a common feature just before and during winter for ages. With the increase in global warming, the migration of birds from the extremely cold regions in the North has undergone distinctive irregularities. In some areas like Canada, the Arctic and Russia's Siberia the number of migratory birds is declining. The process continues at a troubling pace. Many of the approximately 1800 migratory bird species in the world, out of 10,000 in total, are feared to have dropped out of their yearly migrations. As part of the changing process, the number of winter-beaten northern birds taking shelter in Bangladesh and the neighbouring countries also continues to fall. The reasons for this drop, however, centre round shortage of safe shelter and sufficient food in the south. Birds seem to have begun adapting to the present less punishing nature of winter in their native countries.

However, this slowly emerging temperate climate is not a common scenario. Cruel winters still ravage many countries in the northern hemisphere, prompting the desperate species to migrate to their traditional 'second homes'. At the same time, things weird and freakish in nature also keep occurring when it comes to these migratory birds.

The start of birds' migration to Bangladesh this year has coincided with the spotting of a pelican in a village beside the Padma in Rajshahi. The bird is brown in colour. It is one of its eight species found in different parts of the world. Pelicans, seen near seas, are native to North America and Australia. They are mostly white and some have black patches. Parts of Bengal and Assam were habitats of this water bird centuries ago. It has long been considered extinct in the region.

The sighting of a pelican in Bangladesh has thus triggered a normal speculation. Many believe that a group of pelicans detached from a large flock of birds on inter-continental flight may have strayed into Bangladesh. It is not too unusual. Losing contact with the main group and getting lost in an unknown region has been common with migratory birds and animals for ages.

 Many others have discovered in the pelican's spotting in Rajshahi a globally distressing signal: migratory birds may have started changing their flight paths. It means they are in the process of coming away from their traditional destinations owing to the newly developed adversities in those places. Against this backdrop, migrations of newer birds and species alongside the earlier ones to certain areas are viewed by many bird watchers as normal. Bangladesh might emerge as being part of one of these regions. 

The new phenomenon concerning migratory birds is blamed by ornithologists on the worldwide impact of climate change. Dearth of sufficient food and nesting and cruelties let loose on the already harried birds add to the plight of these bewildered creatures. Migratory birds in Bangladesh have long fallen on bad times. Only a few decades ago, nearly 200 species of exotic birds would visit the land during winter. With their varieties gone, the number falling, they now include some common species of cranes and ducks. They include teals like Chhoto Sarali, Boro Sarali, Cotton Pigmy Goose (Balihansh), Snake Birds, Pintali Ducks, etc.

Bangladesh is lucky to be among the lands hosting these wonderful creatures. True, climate change has started taking a toll on birds' normal migrations. It shouldn't be aggravated by proving ourselves hostile to them. Good news is we can expect to see newer exotic guest-birds in the country in the future.

[email protected]