Dear Roarna,

When cold winters come around, thousands of monarch butterflies begin a long journey in search of warmer weather. Some will fly more than 2,200 miles to find it.

That’s what I found out from my friend David James, a scientist here at Washington State University who is studying where monarch butterflies go.

So far, it appears that many monarchs who start their journey in Canada or the Northern U.S. head down to Mexico.

“If a Canadian monarch survives the winter in Mexico, it will fly back to Texas to breed,” James said. “That’s an additional flight of about 800 miles.”

So, it’s likely that some of the butterflies will fly up to 4,000 miles in their lifetime.

Some experts have calculated that’s about the same distance as a 150-pound person making a trip around the Earth 13,000 times. That’s like making a trip from the Earth to the moon more than 500 times.

The journey is long for monarch butterflies. They do it for survival.

“They can’t survive the cold winters in the north, so they leave for the milder climate along the California coast and into Mexico,” James said.

Before the monarchs start heading south, James and other volunteers tag the butterfly wings with an ID code on a little sticker. It’s like a butterfly license plate. Then, he depends on citizen-scientists, people who volunteer their time to help with scientific research, to keep their eyes out for the butterflies.

When people find the tags and report the ID number, it helps James and scientists get a better understanding of the monarchs’ flight pattern. While we don’t know exactly what route the butterflies take, the citizen-scientists are helping us learn more about it.

“We do know they travel 30 to 50 miles a day,” James said. “Sometimes fairly low, across the landscape. I’ve seen them crossing highways just above car-level.”

Some glider pilots have actually spotted monarchs flying hundreds of feet up in the air, James said. The butterflies will use air currents to help them travel.

They rise to the challenge of eating and sleeping along the way. While in flight, they have to keep their wings dry. They’ll stay in trees to escape the rain. Monarchs will fly during the day and in temperatures of at least 55 degrees Fahrenheit. They stop to eat nectar from flowers. At night, they’ll roost in trees.

Most monarchs will arrive in Mexico in early November. When they reach their destination, they roost with about a million other monarchs. You can spot swooping clouds of orange and black coming from the trees.

The butterflies stay in Mexico or California for the winter. Fittingly, they start to find mates in February, around Saint Valentine’s Day. They lay new eggs that hatch caterpillars. The caterpillars change into butterflies and make their way back north. It’s another long journey for a new generation of monarchs.


Dr. Universe