Every year, monarch butterflies travel thousands of miles from their summer homes in northern states and Canada to wintering spots in Mexico and southern California.
In spring, they make the journey back again. However, the butterflies die before they
reach their northern homes. New butterflies, hatched from eggs laid by migrating
monarchs, complete the journey. A scientist wanted to know how the new butterflies
found their way to their northern homes if they had never been there before. Which
of the following is not a testable hypothesis about monarch migratory behavior?