Bird migration is a natural miracle. Some birds fly hundreds and thousands of kilometres to find the best habitats for feeding, breeding and raising their young. There are many different migration patterns. Birds that nest in the Northern Hemisphere tend to migrate northward in the spring to take advantage of rich spring and summer insect populations, fresh plants and perfect nesting locations. Just after summer when the availability of food drops, the birds move south again.
The Globe of Bird Migration is an awesome mapping project by Oliver Queck of Augsburg University of Applied Sciences, that lets you understand how this process actually looks like. It maps the migration paths of 11 different species of birds around the world during a course of the year.
The overall effect is really stunning. The project has been custom coded using the Unity WebGL engine and 3DS Max. Great job!