Human migrationHuman migration is the movement of people from one place to another with intentions of settling, permanently or temporarily, at a new location (geographic region). The movement often occurs over long distances and from one country to another (external migration), but internal migration (within a single country) is also possible; indeed, this is the dominant form of human migration globally. Migration is often associated with better human capital at both individual and household level, and with better access to migration networks, facilitating a possible second move.
Circular migrationCircular migration or repeat migration is the temporary and usually repetitive movement of a migrant worker between home and host areas, typically for the purpose of employment. It represents an established pattern of population mobility, whether cross-country or rural-urban. There are several benefits associated with this migration pattern, including gains in financial capital, human capital, and social capital. There are also costs associated with circular migration, such as brain drain, poor working conditions, forced labor, and the inability to transfer acquired skills to home economies.
International migrationInternational migration occurs when people cross state boundaries and stay in the host state for some minimum length of the time. Migration occurs for many reasons. Many people leave their home countries in order to look for economic opportunities in another country. Others migrate to be with family members who have migrated or because of political conditions in their countries. Education is another reason for international migration, as students pursue their studies abroad, although this migration is often temporary, with a return to the home country after the studies are completed.
Bird migrationBird migration is the regular seasonal movement, often north and south, along a flyway, between breeding and wintering grounds. Many species of bird migrate. Migration carries high costs in predation and mortality, including from hunting by humans, and is driven primarily by the availability of food. It occurs mainly in the northern hemisphere, where birds are funnelled onto specific routes by natural barriers such as the Mediterranean Sea or the Caribbean Sea.
Animal migrationAnimal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of migration in ecology. It is found in all major animal groups, including birds, mammals, fish, reptiles, amphibians, insects, and crustaceans. The cause of migration may be local climate, local availability of food, the season of the year or for mating. To be counted as a true migration, and not just a local dispersal or irruption, the movement of the animals should be an annual or seasonal occurrence, or a major habitat change as part of their life.
