Birds that travel from one place to the other place are called as Migratory Birds.
Hence, travelling of birds from one place to the other place is called as Migration of Birds.
Birds of a species that migrate in summer and live with us in winter are called as the Winter Residents. In the same way, the birds that remain with us in summer and migrate in winter are called as Summer Residents.
The birds that do not stay with us for long and remain migrating from season to season are called as Visitors.
The residents of one season in one area are residents of some other area in another season.
We do not know for sure about – Why do birds migrate? We can just say that they migrate for feeding and reproducing in favourable environments.
Scientists are of the opinion that birds have well developed sense of direction which guides them during their migration. While migrating from one place to the other place birds opt for certain routes. Each bird species is reported to follow the route of migration followed by their ancestors.
However, if certain areas in the route lack proper supply of food, slight deviation in the route of migration is made by the birds. These new or improved routes of migration are called as lanes of migration.
Hunters of birds that remain cunning enough to study the lanes of migration usually stay at certain points of these lanes and kill large numbers of birds in the route of their migration.
In view of this danger, Governments establish bird sanctuaries in the lanes of migration to check hunting and killing of birds in their routes of their migration.
The knowledge of migration lanes is helpful for ornithologists who watch and study different species of birds.
It is due to migration of birds that we happen to see changes in the populations of birds in particular seasons in particular areas. Flocks of birds of particular species are seen in an area in a particular season. But these flocks disappear after some time we may not be sure about.
Some species of birds start migration during days while others start migration during nights.
Some species of birds assemble to form flocks before migration while some species of birds do not assemble to form flocks and disappear suddenly.
Flocking birds are seen here and there sitting together and chirping. These birds are seen sitting on wires and poles and in trees for some days but disappear suddenly.
Some birds do not migrate at all and hence are called as Permanent Residents of an area. The principle applies for some species of pigeons, sparrows, Mynas etc.
Habitat destruction and hunting causes considerable changes in the areas of landing of birds. In South Chhotanagpur areas of Jharkhand Siberian Cranes were reported to visit the land at certain places during winters. But now they are not seen for some years.
Ornithologists are of the opinion that hunting of migratory birds has caused this condition. The public of particular areas falling in the lanes of migration should be made to learn not to kill bird guests. Rather the public should protect them.
Birds, migration, lanes, ornithologists, hunting
