The Monarch’s Journey

Many animals move from one place to another at certain times of the year.This annual movement is called migration.They migrate to find food, seek a partner, or in search of warmer weather.One of the most wonderful migrations in nature is that of the North American monarch butterfly. Every autumn, millions of these beautiful insects with fine black and orange wings begin a long and difficult journey.Somehow they manage to travel around 4，000 kilometres south and find their way to California or Mexico.However, until recently no one knew (1)how they did this.