Anderson Cooper on witnessing the monarch butterfly migration [Video]

This week on 60 Minutes, correspondent Anderson Cooper reports on the migration of the monarch butterflies, an annual spectacle during which millions of butterflies begin their trek north from Mexico, where they have spent the winter. The butterflies have flown south from the U.S. and Canada each fall, and this transnational migration remains one of science’s great mysteries: millions of monarchs know the correct path to migrate even though they have never made the long journey themselves.

For humans, the expedition to see the butterflies’ migration can be its own challenge.

It took the 60 Minutes team three years of planning to produce this week’s story. The window during which butterflies leave their overwintering roosts in Mexico’s pine and fir trees is short and at the mercy of the weather. This year, the temperature was uncooperative for days before the team began shooting.

But first, they had to get there. …