The wonder of migratory birds (The factors which force them to migrate)

Birds are migrating from Europe and Asia to Africa and vice verse.
The movement of birds between parliactic (America & Europe) and Ethiopia (Southern Sahara), Oriental and Ethiopia or Parliactic and Oriental is due to
• Climate Changes
• Time Change
• Food Change

Climate Changes
Winter is cold and makes harsh strong condition to birds. Since birds are worm blood can not with stand such harsh condition so they migrate to tropical worm climate (Ethiopian Region).

Time Change
In winter days are shorter and cold so birds have limited time to eat sufficiently instead they spend much time without moving; that why they have to tropical worm climate.
Food Change (Short food Supply)
In winter field are covered by snow, so seed get covered by snow as well as insect, amphibian and other small mammals go hibernation. This situation is enough to make birds migrate from Parleactic and Oriental to Ethiopian regions where it is worm, long day and food supply is constant