Monarch butterfly on Lovells Island.
For thousands of years, people have followed the rhythm of nature's cycles to inform and enrich their lives. Lengthening days, spring flowers, waves of insects, exploding seeds, turning leaves, and migrating birds were all signals to plant, forage, move, harvest, hunt, or celebrate. Today, scientists call the biological events that mark seasonal transitions "phenological events." Phenology is the study of the causes and consequences of the timing of biological phases.