Scientists study butterfly migration
|Monarch butterflies. (Photo: U.S. Fish & Wildlife Service)|
As winter approaches in North America, hundreds of millions of monarch butterflies take flight, sometimes migrating as many as 3,000 miles to warmer places. For researchers, the key to keeping track of these black and orange insects is a special tagging system.
“In good years, we tag somewhere between 80,000 and 100,000 monarchs,” said Chip Taylor, an insect specialist at the University of Kansas. Taylor runs Monarch Watch, an organization that keeps an eye on the butterflies as they travel.
For the past several years, scientists at a number of research associations have tagged monarch butterflies in order to learn more about their travel routes. The researchers gently press the tags onto the butterflies’ wings so that they can still fly freely. The tags have identification numbers on them and contact information with a number that people can call if they find one of the butterflies.
“Usually people who find these [butterflies] have never heard of our program and are quite astonished when they find a tag,” Taylor told a reporter.
Monarch butterflies are one of nature’s most predictable insects. They stick to a strict schedule, usually passing the same places on almost the same date every year during their journey. The tagging program helps scientists to track those journeys and gives non-scientists a way to help with the study of these miniature travelers.
Some towns hold major events to celebrate the migration of monarch butterflies. Grapevine, a small city north of Dallas, Texas, hosts the annual Butterfly Flutterby festival. Residents can help tag butterflies there, as part of Monarch Watch’s program.
"I've tagged 580 monarchs for release today," said Gayle Hall, the organizer of the festival.
Monarch butterflies travel southward, like birds, often landing in Mexico for the colder months of the year. Most of the monarchs arrive in Mexico at the end of October. Once temperatures warm up, they take to the skies for the flight northward.
The number of migrating monarchs changes every year, depending mostly on weather conditions. Many of the butterflies land west of Mexico City, where scientists perform their official count.
Taylor and the other teams studying monarch butterflies have only been tagging the insects for 14 years. That is not a lot of time, according to Taylor.
“The long-term outlook for the monarchs is not good,” Taylor said.
Deforestation—the destruction of forests—in Mexico is hurting the natural habitat for butterflies in warmer climates. In the United States, the growth of cities is harming their homes. Taylor also thinks that as Earth gets warmer through global climate change, fewer butterflies will be traveling southward.
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Ezra Billinkoff is a contributing writer for Scholastic News Online.