It is now known that the male and females of the Common Tern overwinter in different areas of the west coast of Africa. The couples meet only at the breeding place.
If a couple hatched successfully in the previous year, they usually breed together the following year. There are couples who breed together for many years.
In the courtship time the male fish a lot of fish as a gift for the female.
The better a male can fish, the more likely he is able to catch enough fish for the hungry offspring.
Males who know good fishing grounds are simply the best match.
The young terns mostly come back from Africa in the age of two or three year. They usually do not brood directly, but stay in the colony. They use the time to get more information about the fishing groounds in the area.
A parent which knows where fish is easy to catch has a clear advantage.