Nature Diary

Winter visitors

Just as tourists do, many birds visit India. While they are more abundant in winter, birds visit us in summer as well. These birds have well-defined seasons for their visit, as well as their departure. The same flocks of birds will typically arrive at the same time, to the same place, year after year. This pattern of bird movement is called migration.
Typically, birds migrate in winter from colder places in Europe, even the Arctic, to avoid the cold. More often, they migrate in search of food, when the ground gets frozen and they are not able to find their favourite worms in the frozen soil. Sometimes they migrate away from India to the north in search of long summer days to extend their breeding season. Then they return in winter when food stock gets low.
Most often, the entire flock migrates together. Scientists have found that flying in a regular pattern-formation such as in a V-shape reduces the energy requirement overall. This is critical since birds sometimes fly many thousands of kilometers. In fact the birds gather together and keep on feeding until they have put on enough fat to provide them with energy for the whole journey.
The birds also can fly very high: for example, bar-headed Geese have been seen flying over Himalayan peaks over 8000 m high even when lower mountain passes of 3000 m height were nearby. This may be because of winds and updraughts near high mountains which provide lift and make their flight easier.
This age-old activity of birds repeats regularly with the seasons, with birds flying to well-known earlier locations, where plenty of food and favourbale habitats were found. Because of this regularity, over the years, these locations developed into bird sanctuaries.
There are many bird sanctuaries all over India. Since migratory water birds prefer places where water is plentiful many sanctuaries are near or on lakes, such as Chilka lake in Orissa or Vedanthangal near Chennai in Tamil Nadu.
Birds such as varieties of teals, pintails, wagtails, sand-pipers, cormorants, storks, herons, are found here at this time. The Jacobin cuckoo, however, is known to migrate here just before the monsoon season, in summer.
However, many migratory routes get dispersed due to human disturbances.  For instance, one of the most famous visitors to the Keoladeo National Park at Bharatpur in Rajasthan was the Siberian Crane. Since 2002 it has no longer been sighted there. This crane is a critically endangered species, with just a handful living in the wild. (See picture on the front cover).
Ranganathittu Bird Sanctuary in Karnataka, Kumarakom Bird Sanctuary in Kerala, Nalsrovar Bird Sanctuary in Gujarat, all play host to migratory birds in winter.
Each of these places has its own special or flagship visitor, that visits because of the nature of the habitat, or the availability of particular type of food. By converting these places into wild-life sanctuaries and national parks, the government is putting in place mechanisms to protect these birds and allow them to continue their age-old routine.
In addition, many of these sanctuaries are also home to a number of animals. Why don't you locate a sanctuary close to your home and pay a visit to some of these visitors? Try and find out what types of birds visit, and why.