Conclusion

1. Migration is defined as the regular movement of animals each year between separate breeding and wintering grounds.
2. There are many different types of migratory behaviour, ranging from completely sedentary populations to populations that are completely migratory (obligate migrants).
3. There are three kinds of natural selection that can cause evolutionary change: directional selection, disruptive selection and stabilizing selection.
4. The study of Darwin's finches illustrates how rapidly natural selection can result in a change in phenotype.
5. Homeostasis is an important mechanism for maintaining internal balance. In achieving homeostasis, animals maintain a relatively constant internal environment even when the external environment changes significantly.
6. Birds use both internal maps and compasses to find their way during migration.
7. Olfactory maps and magnetic maps are believed to help birds locate themselves in space.
8. Three internal compasses allow birds to sense the direction in which they are flying. These are the Sun compass, the star compass and the magnetic compass.
9. The mechanisms used by birds to orientate during migration are still largely unknown and are currently the subject of ongoing research.