The best-known form of imprinting is the imprinting of the newly-hatched (or born) on one or both parent. Its function is to keep the young near their parent(s) during the early learning period. It is most obvious in birds, such as ducks and geese, after the fledglings have left the nest. They imprint on their parents and then follow them around, often in a long line, on land and on water.