migrate of organisms

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather, they move to southern part of earth to find foods, and a warmer place to live. Migration is marked by its annual seasonality, they move to south during winter and come back in spring. Every year, they need to fly a long distance for a warmer place to live. And another amazing thing about bird migration is that they use many different ways to navigate themselfs. Many birds have been shown to use a sun compass. Using the sun for direction involves the need for making compensation based on the time. The ability of birds to navigate during migrations cannot be fully explained by endogenous programming, even with the help of responses to environmental cues. The ability to successfully perform long-distance migrations can probably only be fully explained with an accounting for the cognitive ability of the birds to recognize habitats and form mental maps. But sometimes, birds can lose their way and occur outside their normal ranges, there is a term called Reverse Migration, it causesthe genetic programming of young birds fails to work properly, and lead to great rarities turning up as vagrants thousands of kilometres out of range How does bird know when is the time to migration? In a period of time before migration, birds’ body fat increase, so they know it is time to move to another place for winter, and use the fats as energy to fly.