Partial migration is in reference to a species that does not move away from its breeding ground permanently. In a species where the breeding cycles are different, partial migration can occur.
Changing of the seasons causes many species to migrate to a warmer climate. Other types of migration are affected by the seasons and with other variables such as reproduction and terrain.
Climate change is the reason that geese fly south for the winter. The warmer weather allows food and water to be accessible to the animals.
When animals can no longer thrive in a particular area, they must move permanently. These changes can occur from natural causes like flood or fire. Overpopulation is another main cause for this kind of removal.
An animal protecting its young will migrate if it believes the young may become prey. Also, the young may have different needs from the older animals, causing them to change climates or find a different source of food.
