Migration is the relatively long-distance movement of individuals, usually on a seasonal basisThe trigger for the migration may be local climate, local availability of food, the season of the year or for mating reasons. 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, such as birds migating south for the winter is a major habitat change as part of their life |  |
