The other day I was going through an article in the News Paper on " Bird Migration". This reminded me of my two and a half years' of stay at Ghana Bird Sanctuary between 1979 and 1981 when I used to spend lots of time inside the Park roaming and watching the B.N.H.S. people ringing the various species of the birds with the help of the forest staff and local villagers. Watching the process of ringing the birds  then had created lot of curiosity in me and I used to wonder whether the birds really migrate (fly long distances in search of food and shelter). 

    The coming of the cold season in the Indian subcontinent brings with it two of  the most significant developments in the natural world - events that are as spectacular as they are mysterious, journeys that are breathtaking, huge even epic in proportion .        

 One of these journeys touches us all as millions of winged creatures  fly over this entire land mass. " Bird migration " ! Where ever one is, be it city, town or village ; on the coast, on the banks of a river or that of a lake, in the grasslands or in the forests, one cannot miss these birds. Millions of winged denizens from the northern latitudes, flying away form the freezing cold, travel huge distances, traversing through the Himalayan passes, occasionally flying over these mighty mountain to the warmth and comfort of the subcontinent. The diversity too is amazing, be it colour, shape or size. There are the sparrow sized " wagtails " and also the cranes that stand nearly four feet tall ; waders that inhabit the shallow margins of water bodies ; ducks like the pintail ( they have  long pin - like feathers  projecting beyond the tail ) and shovellers ( they have a shovel shaped beak ) and also the harriers ( those graceful and powerful hunters on the wing ), preying on unsuspecting smaller birds, lizards and frogs.

It 's also a huge longitudinal canvas that these birds fly in from : Germany in the west ( About 10°E ) to the shore of Lake Bailkal in Russia ( about 110°E ) In the East, funneling  in, as it were into the Landmass of the subcontinent. These insight into and information about bird - migration have come mainly form bird - ringing, when birds with small, light rings around their legs are caught again in a distant land. Sample this from The Book of Indian Birds by the late Dr. Salim Ali, " It was  by  means of a German - ringed stork accidentally recovered in Bikaner that we now know that some at least of the white storks that visit us in winter are ' 'Made in Germany '.......... Yellow wagtails ringed in Kerala during winter were recovered on passage in Kabul, Afghanistan, the following  spring and at Bannu,  N.W. Pakistan, in the succeeding autumn. A forest wagtail  ringed in Kerala in February  was killed in the Chin Hills of Burma in April . Spanish and Turkestan  sparrows ringed in Bharatpur Rajasthan, in early spring were recovered on their nesting grounds in Kazakstan in summer. "

Migrating birds have evolved an amazing lifestyle , fraught with danger, principally to take advantage of warm summers in the higher latitudes of the northern hemisphere ( summering areas ). Here the  abundance of food helps them rear families . As the winter advances, birds depart to warmer climes further south in the tropics and sub - tropics where food is available ( wintering areas ). In Asia, the Greater Flamingo Phoenicopterus roseus is a notable exception  to this     north - south migration . These large leggy birds breed in the Little and Great Rann of Kutchh in Gujarat and also in western Iran. The seasonality and regularity with which they move between the two countries appear  largely unpredictable and even unknown.

     Birds that breed in the southern hemisphere migrate northward to the tropics. Several species around the world tend to migrate locally within a country, in search of food and water. Such local migration are often driven by the arrival of the monsoons.

 Over time birds become accustomed to preferred routes. Established migratory routes used by a large number of species are designated flyways. Different species of  birds have evolved different strategies and migration routes. Some opt for quick, long leaps - stopping at few places along their journey from nesting  grounds to non-breeding areas. Others have a more leisurely    schedule for their annual travel, stopping at several sites along the way.

whichever style is preferred, the staging site or rest stops are crucial as they provide time for the birds to feed and gather their strength. The migration route followed during northward and southward migration can be quite different, so a staging site may only be used once a year. While birds generally remain faithful to a migration route each year,  some variations in routes have been noticed. So the migration route of the species is the sum of all this. The start and end times of migrations also differ among species. In the case of some shorebirds, flocks of only males, or both male and female adults migrate ahead of  their young ones  who, a few weeks later, mysteriously find their own way south. Cranes and a few other species that enjoy strong family bonds tend to migrate together in small flocks.

The incredible migration of the Arctic Tern Sterna paradisaea  from the Arctic to the Antarctic waters is well documented. Research on the Bristle - thighed  Curlew Numenius  tahitiensis, a shorebird largely restricted to the Pacific Ocean region, has revealed that the birds take off from Aleutian Islands in southern Alaska and fly over the  Pacific Ocean - overflying the Hawaiian islands to land on a few small oceanic islands further south. This involves a non -stop marathon - covering a  distance of 6,100 to 7,100 km. Exactly how the relatively frail birds manage to perform this feat is still a mystery.

The Indian Scenario:
So  where do our ' Indian ' birds come from ? They migrate from across the width of Russia - mainly from east of the Ural mountains, the Central Asian Republics of Kazakhstan, Uzbekistan, Kyrgyzstan, Turkmenistan. Tajikistan, Afghanistan, Azerbaijan, Iran, Pakistan, China, Mongolia, Nepal and Bhutan. We share these species with Bangladesh, Sri Lanka and the Maldives. Collectively, our birds use what the ornithologists call the Central Asian - South Asian flyway.

Some of the best known migrants in India include the  cranes, ducks, geese and swallows.  But there are many more that manage to go unnoticed. And while several species to India can still be counted in their millions,  the population of others is dwindling and some are probably seriously threatened. The Siberian Crane Grus leucogeranus serves as a flagship species to publicise the plight of migratory species, and indeed of Rajasthan's Keoladeo Ghana National Park in Bharatpur.

To answer the questions : Where do they come from ? Where do they go ? Where do they stop ?,  dedicated professionals and amateurs working together in India with others around the region  have pieced together at least a part of the picture. The sustained efforts of the late Dr Salim Ali and his many students and colleagues at the Bombay Natural History Society ( BNHS ), for instance,  provide us with a foundation for bird migration studies. The first study of bird migration in India was conducted as far back as 1959, with a bird ringing project organised by the BNHS.  Unfortunately,  language and other barriers  ( resources ) have not permitted the kind of cooperation and interchange  of information and gap - filling opportunities to map out the migrations of species in this region,  as has been possible in the Americas or western Europe.

Large - scale ringing ( banding ) of birds is one of the popular techniques used to study migration pattern and flyways.  A little metal ring is placed on  the leg of the bird,  to give it an individual identity, after which it is released.When it is recaptured elsewhere ( or shot or trapped for food, as many past recoveries have tended to be ) we learn about one journey of the bird.

Many such journeys, when plotted on a map, help to build up a story of the breeding areas, non - breeding areas and staging sites. This is slow and painstaking work, but the rewards  are well worth the effort ! .

Every movement of a bird followed by a ring and recovery does not necessarily help to understand migration. Osprey chicks have been ringed at their nests in the northern tip of Norway in Europe as part of a study to follow their migration to West Africa. However, four months later one marked individual died when it collided against a high tension power line near Jamnagar in Gujarat. This young bird was certainly way off its normal route - perhaps a victim of inclement weather.

Miniaturisation in electronics has  enabled light, powerful transmitters to be placed on birds to track their movements. Satellite transmitters then help track individuals along their routes and to plot precise stop over points for several species.  According to 'Birds of the India Subcontinent ' by Grimmett, Inskipp and Inskipp, the winter season draws 159 species of birds to the subcontinent, mostly from northern and central Asia. Many enter India from the Indus valley. In recognition of the importance of the Indus plain to migratory birds, in 1967, the IUCN, birdlife International and the International Waterfowl Research Bureau (now Wetlands International ) rated the Indus wetlands as the world's fourth most Important flyway for waterfowl migration.In the northeast, the Brahmaputra and its tributaries form a flyway for birds form northeast Asia into India. Bangladesh and southeast Asia.

During their annual migrations, birds depend on a variety of habitats to feed and rest. They are able to alter their diet depending on availability. Some shorebirds, for example, will feed on a mixed diet of insects and berries on their high Arctic breeding grounds but switch to a largely aquatic invertebrate diet on the inter - tidal mudflats in Gulf of Kutchh in Gujarat and elsewhere on the coasts.  

Birds migration is a phenomenon that connects countries, even continents. If only it could help a little more in connecting the hearts of the people who live along  the thousands of  kilometers these birds travel, the world might actually be a better place. But then, no one asked the birds. In any case for members of the human species, being called birds  brained has always been an insult; rarely if ever, a compliment.