Scientists use radio tags to unlock monarch butterfly migration clues | 60 Minutes

The last minute of 60 Minutes is sponsored by United Healthcare. Coverage you can count on for your whole life ahead. Tonight, an update on last season's story from the mountains of Mexico, where we witness the mysterious migration of monarch butterflies.>> You can actually hear the sound of butterfly wings. >> Yeah. >> Let's just be quiet for a second.Look at that. Look. Look at that.Oh my gosh. It's still something of a mystery how these monarchs find their way thousands of miles from the US to Mexico. Bu ...