Migration (ecology) in the context of "Season"

Overpopulation or overabundance is a state in which the population of a species is larger than the carrying capacity of its environment. This may be caused by increased birth rates, lowered mortality rates, reduced predation or large scale migration, leading to an overabundant species and other animals in the ecosystem competing for food, space, and resources. The animals in an overpopulated area may then be forced to migrate to areas not typically inhabited, or die off without access to necessary resources.

Judgements regarding overpopulation always involve both facts and values. Animals are often judged overpopulated when their numbers cause impacts that people find dangerous, damaging, expensive, or otherwise harmful. Societies may be judged overpopulated when their human numbers cause impacts that degrade ecosystem services, decrease human health and well-being, or crowd other species out of existence.

Animal 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. An annual event could include Northern Hemisphere birds migrating south for the winter, or wildebeest migrating annually for seasonal grazing. A major habitat change could include young Atlantic salmon or sea lamprey leaving the river of their birth when they have reached a few inches in size. Some traditional forms of human migration fit this pattern.

Climate change is posing an increasing threat to global socioeconomic development and environmental sustainability. Developing countries with low adaptive capacity and high vulnerability to the phenomenon are disproportionately affected. Climate change in Kenya is increasingly impacting the lives of Kenya's citizens and the environment. Climate change has led to more frequent extreme weather events like droughts which last longer than usual, irregular and unpredictable rainfall, flooding and increasing temperatures.

The effects of these climatic changes have made already existing challenges with water security, food security and economic growth even more difficult. Harvests and agricultural production which account for about 33% of total Gross Domestic Product (GDP) are also at risk. The increased temperatures, rainfall variability in arid and semi-arid areas, and strong winds associated with tropical cyclones have combined to create favourable conditions for the breeding and migration of pests. An increase in temperature of up to 2.5 °C by 2050 is predicted to increase the frequency of extreme events such as floods and droughts.

Seasonal human migration is the movement of people from one place or another on a seasonal basis. It occurs most commonly due to seasonal shifts in demand for labor. It includes migrations such as moving sheep or cattle to higher elevations during summer to escape the heat and find more forage. Human labor often moves with fruit harvest or to other crops that require manual picking.

The Humboldt penguin (Spheniscus humboldti) is a medium-sized penguin. It resides in South America, along the Pacific coast of Peru and Chile. Its nearest relatives are the African penguin, the Magellanic penguin and the Galápagos penguin. The Humboldt penguin and the cold water current it swims in are both named after the explorer Alexander von Humboldt. The species is listed as vulnerable by the IUCN with no population recovery plan in place. The current wild population is composed of roughly 23,800 mature individuals and is declining. It is a migrant species.

Humboldt penguins nest on islands and rocky coasts, burrowing holes in guano and sometimes using scrapes or caves. In South America the Humboldt penguin is found only along the Pacific coast, and the range of the Humboldt penguin overlaps that of the Magellanic penguin on the central Chilean coast. It is vagrant in Ecuador and Colombia. The Humboldt penguin has been known to live in mixed species colonies with the Magellanic penguin in at least two different locations at the south of Chile.