Climate change does not spare even migratory birds

Shihab Sarkar | Published: November 29, 2018 21:36:33 | Updated: November 30, 2018 21:15:30


Owing to the continued hunting of migratory birds during winter, traditional bird sanctuaries in the country have been experiencing a decline in the arrival of the avian guests. The age-old temporary safe-shelters of these birds have witnessed the drop in an increasing degree for the last few years. These sanctuaries once earned the reputation of Bangladesh as a country friendly to migratory birds. To the woes of bird lovers and environmentalists, the guest birds are now being seen flocking to newer spots in the country. On the other hand, fast squeezing of water bodies like 'haors' and 'beels' is also attributed to the birds' diminishing preference for this country as a whole.

The strictly guarded sanctuaries like the Jahangirnagar University campus on the Dhaka suburb, the large 'haors' and other water bodies in the country's northeastern and northern regions still draw passionate and inquisitive bird watchers. A great number of them are seen travelling to the other spots, most of them newly discovered. According to bird enthusiasts and ornithologists, the migratory birds may have developed a premonition of hazards during their stay in Bangladesh. And it may have prompted the helpless avian creatures to disperse themselves across the whole country. The areas are not necessarily gifted with expansive water bodies. But they are distinctive with their remoteness and tranquility.

The developments vis-à-vis the arrival of guest birds in Bangladesh could be defined as a sad commentary on the country's treatment of wildlife in general. Bangladesh may not be alone in this cruelty meted out to the migratory birds. In the warmer regions, it is the poorer and unlettered segments in a number of nations who remain engaged in trapping birds, and selling those at markets to clients having a liking for exotic meat. The so-called educated people do not lag behind. They go straight for hunting them with guns. All this savagery ends up being an orgy of unexpected catastrophes for the already cold-battered birds flying thousands of miles to warmer zones.

Few people in the sub-tropical region pause to think about the hostile situation in which the poor birds are made to fly into. In fact, the very process of bird migration began with the movement of vast ice sheets. Geologists believe more than 20 glacial cycles have changed places in the last 2.5 million years. The shifting of polar ice sheets prompted changes in global temperature, leading to differences in the world's climate.

In spite of a raft of newer discoveries in the recent years, the navigation of birds remained an enigma until recently. Although a section of scientists felt it in the 1960s, researchers in Germany and Sweden have lately identified the migratory birds' ability to sense the magnetic field of the Earth and navigate long distances. They are now focused on the finding that birds can actually 'visualise' the magnetosphere below. In the past, bird specialists used to say that cells rich in iron in the birds' beaks aided their navigation. Earlier, a lot of now-discarded theories would define the navigational wonders of the birds and many other roaming animals. In the perspective of the whole animal kingdom, the latest theory of 'magnetoreception' applies to no other species more accurately than to the birds. Scientists have simplified the jargon-filled explanation of the migratory birds' navigation. According to them, "Migratory birds use a magnetic compass in their eyes for navigation." The sensory mechanisms of the magnetic compass have long remained unexplained. New researches reveal exactly where in the bird's eye the control centre for navigation operates.

In spite of the series of new revelations about avian navigation, the whole phenomenon still remains shrouded in layers of riddle. In the distant past, different mythological tales were associated with the birds' intercontinental migration. Those were later replaced by presumptive scientific theories. The most widely accepted among them were the birds' strong understanding of wind directions and their power to smell. Against this hazy backdrop, the magnetoreception theory has literally brought about a revolution. It explains a number of startling enigmas. Not long ago, a group of scientists have homed in on a particular type of 'cryptochrome protein' /in birds' retinas. The protein is sensitive to blue light -- including that emanating from the Earth's magnetic field. This blue light-sensitivity is not confined to birds and a few other animals only. Plants are also known to contain photoreceptive cells, which are believed to respond to blue light.

So much for scientific probes into the mystery of the migratory birds' flights. Insensitive and environment-hostile people around the globe continue to swoop on these creatures, one of the most amazing and lovable of the creations of nature. Already the impact of global climate change has exacted a heavy toll on the birds' flight pattern. With their earlier sheltering sites becoming scattered thanks to h brutality and encroachment on their sanctuaries, it is their population which is eventually set to bear with the heat. Barring environmental activists, few can realise the approaching disaster set to be prompted by the dwindling population of the migratory birds. The most prominent impact of dislocation of these avian creatures is apprehended to be set off in the form of a global loss of biodiversity. Being a country situated on the cross path of the world's two migratory birds' flyways, Bangladesh might emerge as a helpless victim of biodiversity disruptions.

These scientific analyses of avian navigation are not expected to have any remarkable impact on the bird hunters -- be they in Bangladesh or elsewhere in the world. In many countries in South Asia and Sub-Saharan countries in Africa, many communities earn their living by hunting wild birds. With their numbers dropping, these people have started shifting their focus on the migratory birds. In Bangladesh, trapping these birds and later selling them in the market has long become a profession for the poorer segments in society. Thanks to the slapping of a government ban on catching guest birds, the practice has lately undergone a noticeable decline. But who'll deter the relatively affluent and adventure-loving people for whom winter arrives every year filled with the thrill of hunting. Maybe, it hardly occurs to them that by killing the shelter-seeking overseas birds, they are directly contributing to the loss of biodiversity in the country. Moreover, they care a fig about the fact that killing birds in a land which is strange to them but generally hospitable assumes the proportions of extreme brutality. The poorer hunters can be restrained, not them. Due to their privileged position in society, they mostly go scot-free.

Despite Bangladesh being a member of the IUCN (International Union for Conservation of Nature) and the continued rise in biodiversity-saving activists in the country, the hostilities to guest birds go on unabated. As a result, these birds have already started skirting Bangladesh in their intercontinental flights. Even birds from the nearby Himalayan region, long familiar to the country's swamps, are changing their flight courses into other directions. All this potently adds to the insensitivity of a section of people in the country in terms of environmental protection.

shihabskr@ymail.com

 

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