Watch: Monarch Butterflies Get Tiny Radio Trackers

The scientists place a tiny, lightweight radio tag on a migrating monarch butterfly.

While monarch butterflies may be relatively small in size, they make one of the most epic journeys known to animal-kind. During the spring, the first generation of butterflies leaves its winter home in Mexico or California to head north. Each successive generation flies even farther north, ending with the fourth generation finally making it to its summer destination in the northern United States or Canada. When the time comes to head south again for the winter, the fourth generation makes the entire journey back by itself, returning to almost exactly the same spot from which the first generation took off, even though the fourth generation has never been to that location before and there are no earlier surviving generations around to show the way.

Just how monarchs make such a phenomenal 5,000-mile round-trip migration is what ecologist and National Geographic Emerging Explorer Martin Wikelski is trying to understand. “The monarchs’ migration is really like in the old days when settlers went west. How do they know where to go, and when do they decide, Oh, I’m now the fourth generation. I go south, it’s winter? What is that?” Wikelski asks in wonderment, then postures some theories: “The last generation probably measures day length. It realizes that the days are getting shorter, maybe also the temperature gets colder, and then they realize it’s time to go south. But we also think it’s probably swarm intelligence, because they see each other and then they join the crowd and go south.”

Scientists place a tiny, lightweight radio tag on a monarch butterfly.

A few years back Wikelski, along with monarch butterfly expert Chip Taylor, successfully placed electronic tags on free-flying, migrating monarch butterflies for the first time. While Wikelski hopes that tracking the butterflies will lend more insight into how monarchs pull off such an —> Read More