While the controversial issue of immigration continues to plague the entire world, when we look closer at the phenomenon we will eventually realise that in a world beyond anthropocentric considerations, our winged friends undertake a similar journey, seasonally, cutting across boundaries and nationalities, flying thousands of miles to meet their basic need - survival.
Birds migrate for a variety of reasons ranging from food availability, habitat, weather and furthering progeny. It is usually seen that the regular seasonal movement of birds takes place in a North-South direction in the Northern Hemisphere since sub-zero temperatures are recorded in the extreme latitudes of the Northern Hemisphere and the birds seek warmer places to breed and survive these winter months. The Southern Hemisphere too witnesses a similar movement in the opposite direction, but owing to lack of sufficient land, long-distance migration is minimally recorded here. However, as the winter slowly recedes from these tropical areas and gradual warmth sets in, the birds again take a recourse to return to their original habitats. We can therefore safely claim that these birds prioritise comfort and survival, seeking to get the best of both sides.
Historically, migration of Storks, Turtle Doves and Swallows have been noticed by ancient Greek authors like Homer and Aristotle. In contemporary times, the Arctic Tern holds the record for the longest migration covering approximately 71,000 kilometres! Similarly various beautiful migratory birds flock the Indian subcontinent including Siberian Cranes, Amur Falcon, Greater Flamingo, Bluethroat etc and add to the rich biological diversity that our country possesses. However, the sailing is not always smooth for these birds as they encounter a lot of problems en route to their winter destinations. They face immense amounts of exhaustion having to travel for long hours without rest (with rising sea level and more land getting submerged, it will become increasingly difficult for these birds to take adequate rest and recuperate) and many of them falter in flight. Moreover, they even face acute shortage of food due to worldwide habitat destruction by humans. Brazen and uncontrolled deforestation have robbed such birds of stopover shelters and nutrition. Also, with the recent construction of high-rises, turbines, high-electric poles and flyovers their natural pathways are often blocked and tens of thousands of birds collide against these structures at high speed, resulting in serious permanent damage to their body. We must also not rule out poaching of rare birds that are hunted down for their body parts which are sold in the black market against very profitable bargains.
Most importantly, climate change has had the ultimate influence on such migrations. When the sole purpose of migration was to escape sub-zero temperatures and settle for something moderately cooler, habitats like the Chilika Lake along with other coastal wetlands of India have become significantly warmer (than normal) resulting in fewer birds stopping over. S. Balachandran, Deputy Director of Bombay Natural History Society observes that the ideal habitat for these birds is also being destroyed due to change in rainfall pattern. Emphasizing the importance of stopover sites utilised by birds to build energy reserves before a long migratory sojourn, Balachandran said that some sites are conventionally and conveniently used by the birds to build body mass to endure the journey. Pollution in the NCR region has severely affected the migration of these birds as is evident from the low and unseasonal turnout in the Sultanpur National Park where a record spotting of 18 species (a decade back) has dropped to a few cormorants and varieties of wagtails only.
With increasing urbanisation, deforestation, pollution, decreasing groundwater levels and shrinking habitats, there is a crisis of bird migration worldwide. It is interesting to note that in the initial days of the nationwide lockdown, lakhs of flamingos flocked Mumbai, undisturbed by the usual hubbub of city-life. Several protective measures including preservation of natural habitats, minimising use of pesticides, encouraging 'lights out' campaigns, controlling air pollution and stringent penalties on illegal poaching have already been suggested. Green Crusaders hopes that these are urgently implemented or else we stand to lose another wing of our rich biodiversity. Their freedom lies in our hands!
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