“I am happy to know that not all species are forced to need passports and visas to experience new lands.”Rajesh, Author of Random Cosmos
Bird migration has evoked the imagination of many in the past and despite a great deal of inquiry into this mass phenomenon, much remains enigmatic about the great cyclical movement of the avian populations through the planet, which works in a rhythmic fashion similar to the tides of the season. Out of the 1300 species that thrive in the lap of the Indian subcontinent as many as 380 species of birds take on a perilous journey that not only shape the lives of their own but also countless habitats dotted across the vast reaches of the subcontinent. The questions that continue to persist in the minds of many are how and why do these fascinating beings glide halfway across the world to the many ecological biomes around us.
Before we dive into some of the questions that ornithologist and scientists have tapped into, here are some notable hotspots for birders and wildlife enthusiast alike to witness a resplendent show of migratory birds –
Best Places to See Migratory Birds in India:
|Location||A Few Highlights|
|Keoladeo National Park||Great White Pelicans, Greylag Goose, Bluethroat|
|Khichan Village||Demoiselle Cranes, Ruff, Northern Shoveler|
|Desert National Park||Grey Hypocolius, Red-necked Phalarope, European Roller|
|Sultanpur National Park||Greater Flamingo, Eurasian Widgeon, Northern Pintail|
|Chilika Lake||Great Knot, Lesser Flamingo, Black Tailed Godwit,|
|Bhigwan Bird Sanctuary||Lesser Flamingo, Curlew Sandpiper, Collard Pratincole|
|Little Rann of Kutch||Lesser Flamingo, Common Crane, Pied Avocet|
|Nalsarover Bird Sanctuary||White Tailed Lapwing, White Stork, Baillon’s Crake|
|Raganathitthu Bird Sanctuary||Painted Stork, Eurasain Spoonbill, Greater Spotted Eagle|
|Nelapattu Bird Sanctuary||Greater Flamingo, Garganey, Common Teal|
|Kaziranga National Park||Spot-billed Pelican, Bar Headed Goose, Black-necked Crane|
|Nameri National Park||Ibisbill, Ferruginous Pochard, Mallard|
|Pangti||Amur Falcon, Lesser Kestrel|
Out of the list, two of the largest single species migrant bird congregations in India are mentioned below:
- Khichan is a conservation success story based on a village in the Thar Desert of Rajashtan which was pioneered by a man named Mr. Ratan Lal Maloo aka The Birdman of Khichan who would often feed pigeons, sparrows, palm squirrels and the occasional peafowl. Initially, it was the familiar individuals that would come by for a meal but gradually Demoiselle Cranes began frequenting the farmlands. What started with a miniscule number of 80 soon turned into one of the largest congregations with numbers ranging from 12000 to 15000 of these visitors from the regions of Mongolia, Tibet and Northern China. Though Mr. Manloo is no more, the tradition of feeding the birds is still carried out by the community which has resulted in Khichan being declared A Bird Sanctuary and a UNESCO World Heritage Site.
- Pangti is considered as a passage haven for the largest congregation and the longest migration for any raptor species in the world. Nestled in northern Nagaland, the skies of village Pangti are covered in clouds of Amur Falcons hawking for insects every October – November. These pigeon sized birds of prey hail from their breeding grounds in South Eastern Siberia and Northern China and layover in parts of Nagaland, Manipur and Assam of India during the course of their voyage to Southern Africa. The entire journey is an astounding 22,000 km. While there have been massacres in the past for consumption as bush meat, recent efforts to raise awareness and building alternatives as sources of income has curbed the situation.
Now, coming back to…
Why Birds Migrate?
- Seasonal Changes: In the higher latitudes of our planet, the mercury dips to subzero temperatures where life more often than not ceases to exist. With very little food production coupled with extreme weather, the strenuous conditions can test the physiological limits of any species. Due to this, escaping their predicament becomes a highly motivating factor to which many birds have adapted to, travelling over large distances to find the means for nesting and sustenance.
- Food Scarcity: This can be linked with the changing seasons as well habitat degradation. Many species are depended on consistent supply of nutrition through the year, but the only thing constant seems to be change. Through many years, birds have sought for temporary havens when home gets either a bit unbearable or non-existent. During these times there is very little to almost no food to feed the majority of the dwellers. Birds therefore take advantage of a variety of food sources as the seasons change.
- Breeding: Over lifetimes, birds have evolved to seek the ideal conditions to raise their young in an environment that ticks boxes such as a consistent supply of nourishment, a conducive climate that offers ease and comfort and adequate shelter for protection. For any chick, a healthy and reliable environment during infancy is extremely crucial as some of these species fledge their nests for the very first time without the aid of their parents.
- Protection from Predators: Habitats teeming with birdlife eventually turns into a hunting ground for predators. This could be in the form of wildlife, birds of prey, domesticated animals and possibly even human beings. In order to survive a perpetual onslaught, birds migrate to different regions and habitats to not only protect themselves but to also give their young a far better chance of reaching maturity.
How do Birds Navigate?
It’s absolutely mind boggling to witness birds migrate over long distances. Not only do they seem to remember specific geographical locations but also the very tree they nested on. It’s safe to say, that while we as human beings have gotten increasingly dependent on our maps, road signs and the GPS to gauge the distance to the closest supermarket, birds have several homing tools that help them navigate across continents. Here’s a list of some of the most noteworthy –
- Geographic Mapping: A bird’s eye view encompasses a topographical conglomeration which holds mountains, canyons, coastlines, wetlands, woodlands, farmland and rivers. These geological landforms serve as signs and pit stops through the course of countless avian journeys.
- Solar and Stellar Navigation: The circadian rhythm of most species are linked with celestial bodies. Birds like other beings are tuned in to their ‘internal clock’ and the positioning of sun that give them a sense of direction while piloting through flyways. The night is the best time for small passerines like warblers to migrate undetected under from the radars of most predators. It is said that these little brown and green jobs observe the constellations in the night sky to move through the shadows of the night, leading them closer to their ideal home away from home.
- Earth’s Magnetic Field: In recent years, much to the speculation of experts, birds actually do have an inbuilt compass that orients itself to the magnetic field of our planet. With certain proteins called cryptochromes (photoreceptors sensitive to blue light) lodged in their skull, between the eyes, birds have the ability to visually sense the earth’s magnetic field. The protein imbedded within them acts as a filter over their vision which leads them to their preferred destination.
- Memory: If it wasn’t for birds travelling in families or large flocks in certain species, many juveniles would find it rather challenging to seek suitable habitats for feeding and eventual nesting. Observing the flyways, the formations adopted by the flock helps them imbibe many techniques that would later help in them in their own expeditions to find similar refuges in times of food scarcity, seasonal changes or to rear chicks of their own.
What are the Adaptations of Migratory Birds?
Having looked into the homing capacity of birds, the physiological capabilities that propels them take on such arduous journeys poses another question amongst birders. Here, the most suited answers lie in their behavior and evolution –
- Before undertaking an extensive voyage, hormones present in certain species compels them to ‘fatten up’ so that they can use this reserve as they cover a considerable amount of distance. Some birds stock up nutrition to such an extent that they double in size. However, this adaptation is crucial as they burn copious amounts of energy (Almost half their bodyweight) till they layover to refuel for another flight.
- Many birds overtime face challenges like the ones mentioned above in the article. The extensions in wingspan along with pointed tips as opposed to rounded one’s increases aerodynamics. This also reduces the air resistance while simultaneously giving them an uplift thrust to gain altitude. Birds such as geese, ducks, terns use this to their advantage, while larger wingspans aids storks, cranes and birds of prey to soar using thermals during the day as they expend minimal energy while maintaining optimal efficiency.
- In species that face challenges such as hypoxia, high altitudes and freezing temperatures, cardiovascular and respiratory systems have developed to counter the effects of such colossal pressures. Birds like the Bar Headed Goose and Ruddy Shelduck are prime exemplars of species that fly over the Himalayan range as they overcome these extraordinary feats.
What is the Significance of Migratory Birds?
We might not be able to see it in real time but migratory birds serve as major cog in the functioning of the web of life. From seed dispersal to pest control, birds continue to mould our world for the better. They are the essential components of our living planet that maintain a fundamental homeostasis. Without them, the landscape of our planet would be drastically altered.
- Agents of Pest Control: Needles to say, that if birds disappeared from our world, we would be plagued by swarms of insects that would devour almost everything in their path. It would cause mass hysteria as ecosystems would perish within months with nothing to keep populations of insects under regulation. Birds are notorious for consuming heaps of insects, this number can go upto 400-500 million tons per year. They are known to feed on molluscs as well which could potentially wipe out wetlands if left unchecked.
- Landscape Architects: They are the proficient gardeners and farmers we need as they play an active role in seed dispersion which shapes countless landscapes through the world. Acting as dispersers, birds carry different species of plants from one part of the world to another. As they set foot onto a new habitat, the seeds germinate and sprout into life. This ensures the renewal of plants and ecosystems that oxygenate our planet while cycling harmful pollutants that could potentially harm us. The ripple effect certainly has great benefits.
- Decomposers: Certain species are specialist at this as they scour for carrion. Vultures are known as nature’s cleanup crew as they consume carcasses within hours. They go through flesh in a manner that leaves very little to rot and without them there would be a surge in the populations of feral animals which would consequentially lead to an increase in diseases transmitted between them. Without these decomposers, we would be far more susceptible to contagious infections from wildlife.
- Seasonal Indicators: If birds migrate due to changes in season, they are perhaps great indicators of the onset of one. Being far more tuned in to wind directions and the subtlest changes in weather, observing bird migrations can inform us about the inbound seasonal transition. Seeing Jacobin’s Cuckoos during the advent of pre monsoons is an accurate sign that a spell of monsoon showers across India is around the corner.
- A Birdwatcher’s Delight: if it wasn’t for birds thronging in massive congregations in pristine habitats, birders would miss out on some of the most marvelous spectacles of the natural world. Observing birds flying over in symmetrical formations and nesting in large colonies is an absolute joy for many. A world without bird migrations would certainly lack the colour and exuberance many crave to witness.
What are the Threats to Migratory Birds?
Speaking on the ecological significance of migratory birds, it’s also important to understand the threats posed to them, whether natural or man related –
- Predators: Not only wildlife but a significant feral population is the cause for the decimation of countless species. With the domestication of dogs and cats on the rise, many waterfowl species around farmland and wetlands are subjected to hunting. A further spike in these animal numbers will endanger many migratory birds that are already highly vulnerable.
- Disease: Another peril which is detrimental to large congregations of birds is contagion through bacteria and viruses that could possibly kill large wintering flocks in a specific area. It happened in the state of Rajasthan last year where over 18,000 birds fell victim to avian botulism (a neuromuscular illness caused by toxin produced by a bacteria called Clostridium botulinum).
- Poaching: Whether it’s for meat, game or wildlife trade, migratory birds often fall prey to hunting by human beings. In India, this has been recorded amongst tribes and rural folk where communities occasionally subsist on game meat. In Nagaland, thousands of Amur Falcons are massacred during their passage through the state. However, measures are being taken to raise awareness amongst locals which will serve as pivotal point in the future to protect these highly endangered birds of prey.
- Climate Change: is probably the biggest threat that looms over populations of birds over the world. With unpredictable change in seasons it becomes difficult for birds to anticipate the ideal time to migrate as food becomes scarce and areas for nesting coming under stiff competition.
- Habitat Degradation: With development at the forefront of our civilization; energy projects, agricultural takeover and establishment of residential areas across the country have left many wetland, woodland and river ecosystems desolate and depleted. This has left very little room for migratory birds to flourish. Isolated in smaller areas, birds face all of the above challenges as they undertake the grueling task to survive.