The first generation made the long journey and survived a very long, hard rest in Mexico, then started the journey south were they laid the first egg of a new generation.
The second generation emerged, grew, and traveled on south.
The third generation emerged, grew, and traveled on south.
The fourth generation emerged, grew, and prepared to travel north.
The fifth generation, will there be time. Some years they do make it and also travel north, but no one knows how far they get.
I have a fifth generation in my tent now. I spent a few hours this morning protecting them from predators. I hope the weather holds and I don't have to express mail them again.