Question

Birds do not have GPS installed in them yet they reach their desired destination during the process of migration. How?

Answer 1

Because they have natural power of sensation

Answer 2

An observation suggests that migratory birds can detect the earth's magnetic field lines that appear to emerge from south pole and merge into north pole. When migratory birds have to travel from north to south or vice versa, they align themselves with the magnetic field lines and travel to their location.

Along with this, migratory birds may also find their way by creating a mental map of their route using mountains, rivers, etc. Besides this, it is also believed that migratory birds use the location of the sun and stars to find their way and reach the same location.