MigrationMigration is the movement or journey made by animals to places outside their natural environment over a long period of time (Dingle 2007). Typically, during migration, animals look for a sustainable location with many of the necessary resources available. Some animals migrate back and forth between the same areas while others avoid returning to the same area. A rule of thumb when discussing where animals migrate is to look at the animal's lifespan. Animals with longer lifespans tend to return to their original location over time, while animals with shorter lifespans tend to continue in new locations over time. At least one organism within each of the five vertebrate classes has been documented to participate in migration. Next, the migration of fish (especially salmon) and birds will be discussed in more depth, but first a basic understanding of migration and everything that needs to be clear will be provided. There are many ways to track animal migration, and tracking methods have been improved over time. The American naturalist John James Audubon, in 1803, was the first documented person to question and somehow follow the migration of birds. He wondered whether or not a group of migratory birds that left for the winter would return in the summer. To test this, he tied a rope around the leg of one of the birds in question and waited. To his satisfaction, the bird with the rope around its leg did indeed return north for the summer. For obvious reasons this wasn't considered the most accurate form of tracking, but it was a start. Another method used to track animals is called radio tracking. Radio tracking involved two components; the transmitter and the receiver. The transmitter was... middle of paper... to a decrease in the overall salmon population which in turn can have repercussions on the fishing industry and even more so on the economy.ConclusionIn conclusion, not all migrations occur in the same way or is even triggered by the same things. While some migrations are triggered by genetics, other migrations can be learned over time or can be forced due to the need for resources. The resources that can drive this movement of animals are not only food, water and shelter, but also the need for reproductive advantages. Whether it's internal compasses or biological clocks, something contributes to an individual's need for movement and survival. As shown when comparing salmon and birds; both animals must migrate. Although the reasons and ways are different, the general need is still present, making this a very important aspect when studying animal movement and behavior.