Migration of Monarch Butterflies

Here is another wonder of nature. I knew about Monarch migration, but did not know that it can take up to 5 generations for the butterflies to reach Mexico from the US and Canada. Now that is the ultimate in programming!
There are two videos on this link, but they are not clear. Here is a NY Times article that does some good explanation. When you get to the you tuvbe site, you can look at butterfly videos to your heart's content.