MIRZA, Jan 10 - Hundreds of thousands of migratory birds have taken up temporary shelter on the Brahmaputra river and its nearby waterbodies and forests of south Kamrup, after traversing thousands of kilometres, this winter turning the Brahmaputra and its surrounding forests and waterbodies like Deepor beel, Darabeel, Chandubi beel etc., a visual treat for tourists and picnickers, coming to these spots to celebrate the new year.
Experts said that between 1500 and 4000 species of birds are known to migrate from one place to another, all over the world. Out of over 2000 species and sub-species found in India and south Asia, nearly 350 are reported to be migratory in nature. It is estimated that over 100 species of migratory birds fly into India, either in search of food or to escape the severe winter of their native habitats. In the Indian subcontinent, the majority of migratory birds are winter migrants.
It has been reported that migratory water birds such as black stork (Ciconia nigra), great white pelican (Palecanus onocrotalus), greylag goose (Anser anser), barheaded goose (Anser indicus), pintail duck (Anas acuta), northern pintail ( Anus acuata), mallard duck (Anas platyrhynchos), gadwall duck (Anas strepera), common teal (Anas crecca), shoveller (Anas clypeata), northern shoveller (Anus clypeata), common pochard (Aythya ferina), redcrested pochard (Netta rufina), baer�s pochard (Aythya baeri), tufted pochard Aythya fuligula), green sandpiper (Tringa ochropus), Indian tern (Chlidonias hybrida), common tern (Sterna hirundo), large egret (Egreta alba), painted stork (Mycteria leucocephala), brahminy shelduck ( Tadorna ferruginea), common shelduck (Tadorna tadorna), marbled teal (Marmaronetta angustirostris) have been beautifying the Brahmaputra river and its shores.
Sources said that predator birds such as sparrow hawk (Accipiter nisus), fish hawk (Pandion haliatus), pallas�s fish eagle (Haliaeetus leucoryphus), hen harrier (Circus cyaneus), eastern imperial eagle, tawny eagle (Aquila rapax), merlin (Falco columbarius), amur falcon (Falco amurensis), pale harrier (Circus macrourus) etc., have also hovering in the sky and also roosting in the trees after visiting thousands of miles through difficult terrain to Assam during this winter from the arctic countries, Australia and some European countries.
According to experts, these migratory water birds have been visiting south Kamrup from the extreme colder northern regions of Arctic, Europe, Siberia, North America, and areas USA, Eurasia, Russia, Australia, Persian Gulf etc. every year. During winter, there is little food and temperatures dip very low in some of those regions, but in case of countries of the southern regions including India, Sri Lanka, Pakistan and nations of Africa, there is more food supply and relatively warmer weather, leading to the migration.
Sources said that some other migratory birds visiting south Kamrup in particular and Assam in general are little bustard (Otis tetrax), greyheaded lapwing (Vanellus indicus), lapwing (Vanellus vanellus), rufous turtle dove (Steptopelia orientalis), hoopoe (Upupa epops), skylark (Alauda arvensis), redbacked shrike (Lanius collurio), brown shrike (Lanius criatatus), Cetti�s warbler (Cettia cetti), paddyfield warbler (Acrocephalus agricola), white wagtail (Motacilla alba), yellow wagtail (Motacilla fleva) etc.
Sources said that migratory birds use several methods to navigate their way during migration. Many birds use celestial navigation and some of the birds even detect the positions of sun, stars and moon and thereby navigate their ways to locate their destinations . Some birds can even detect ultraviolet radiations emitted by the sun, sources said, adding that, some use topographical landmarks such as mountains, river valleys, and forests to orient themselves on the migration route. Many birds, especially seabirds, identify their destinations by characteristic odours, sources said.
