NA species migrate on a north-south axis due to the fact that their wintering ranges lie south of their breeding ranges as well as the fact that the major mountain ranges in this region also follow this direction, such as the Appalachian or Rocky Mountains, preventing lateral travel. Species in EU and Asia migrate in a East to West direction due to the presence of major mountain ranges and deserts that spread on this axis such as the Alps and the Greater deserts of the middle east. These routes are sometimes fixed, ie species that have colonized a new land will occasionally return to their ancestral territory before embarking or they will eventually realign with the traditional route.
Recent comments