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September 30, 2010

Tagging a Butterfly

Thousands of tiny ID tags can trace the monarch’s incredible two-way journey

  • A monarch sips nectar on a mid-September morning as it begins its migration to central Mexico. Debra Firmani

  • A monarch's tiny feet tickle slightly when it alights on a young participant's wrist. Debra Firmani

  • Eleven-year-old Kyle Evans, who hopes to become an entomologist, observes a monarch he carefully captured. Debra Firmani

  • Sometimes a monarch lingers a few extra moments, allowing a closer look. Debra Firmani

  • Snug in their chrysalises, caterpillars raised at the nature center are transforming themselves into monarchs. Debra Firmani

  • The two tiny spots on the hind wings of this monarch are scent sacs, indicating he is a male. Debra Firmani

  • On the right, an emerging monarch pumps fluid from his abdomen into his wings; the left-hand monarch's wings are nearly full grown. Debra Firmani

  • You can make a difference for monarchs, especially during migration, by planting host and nectar plants. Debra Firmani

  • Tagging these fragile creatures is a delicate process. Debra Firmani

by Debra Firmani

There were nearly 40 of us that mid-September morning—from toddlers to retirees—all eager to see monarch butterflies being tagged as they began their epic migration to the oyamel fir forests in a small area of mountaintops in central Mexico. As the morning sun warmed the meadow grasses, the monarchs took wing, glowing against a dazzling blue sky.

At this Audubon Society of Central Maryland sanctuary, 55 of the many monarchs stopping to sip nectar from wildflowers on their way south were gently captured in butterfly nets, tagged, and released. Borrowing a few moments of these monarchs’ time to give them identification tags means their individual journeys may add to the world’s understanding of an extraordinary migration phenomenon.

The tiny tags—only two percent of the monarch’s weight—are placed on the strongest part of the wing. So far, they’re not known to cause harm or hinder migration. Monarch Watch, a University of Kansas-based program that began involving volunteers in tagging monarchs during fall migration in 1992, makes the identification tags available and posts its database of tagged and recovered monarchs online. 

Why tag monarchs?

Monarchs are unique among North America’s insects in making a two-way migration, traveling up to 3,000 miles on the southward journey if starting from Canada. In spring, they return to the southernmost states, filling out their northern range with successive generations as emerging milkweed makes way for them to lay their eggs.

Here are a few questions the Monarch Watch tagging program helps researchers answer:

  • What pathways do migrating monarchs take?
  • How does weather influence migration speed and stopover behavior?
  • What differences in migration occur from year to year?

How do the tags work?

Each tiny, all-weather, adhesive-backed tag is imprinted with Monarch Watch’s phone number, email address, and a unique identifying number. Tag kits can be ordered by individuals, and the tag numbers issued to each recipient are recorded in a database, so recovered tags can be traced back to the butterfly’s tagging location. The growing number of start and end points helps researchers test hypotheses about monarch orientation and navigation.

How do you tag a butterfly?

If you live east of the Rocky Mountains and would like to tag monarchs, find out when peak migration occurs in your area and order your tag kit and a good butterfly net by visiting Monarch Watch.

  • The first step in tagging is the capture. Approach slowly from behind while the monarch is feeding and use a butterfly net at least 24 inches deep (toy ones can harm butterflies). Sweep the net forward and carefully flip the end over the handle, keeping the butterfly in the deep end of the net.
  • Follow the tagging kit directions for gently removing the monarch from the net and check the wings to determine whether it is male or female.
  • Remove a tag from the sheet using a toothpick, then carefully apply it to the mitten-shaped discal cell on the underside of the monarch’s hind wing.
  • Enter the information on your data sheet, and quickly release the monarch to continue the southward journey.
  • When you have tagged as many monarchs as you intend to tag, return your data sheet and any unused tags to Monarch Watch.

A final word

Tagging is a wonderful way to learn about monarchs while contributing to conservation and research efforts that will help ensure a bright future for an amazing creature who faces many environmental challenges.

Help monarchs in other ways

  • Plant a Monarch Waystation—they’ll find even a small patch of plants they like. 
  • Support habitat conservation in your area. 
  • Manage your own property without using pesticides. 
  • Keep a monarch journal or calendar, and submit data to Monarch Watch
  • If you find a tagged monarch on the ground, contact Monarch Watch.

Online resources

» Monarch Watch
» Journey North
» Cooperative Extension Offices 
» The Monarch Larva Monitoring Project
» Project Monarch Health
» The Xerces Society

Create a sanctuary

Enjoy the company of your wild neighbors in your own yard. Every day, more and more wildlife habitat is lost to the spread of development. But you can help wild animals in urban and suburban areas by offering them sanctuary in your own backyard (or front yard, roof-top garden, or deck), no matter how small. Learn how your green space can become an Urban Wildlife Sanctuary.

Debra Firmani is a writer and long-time advocate for animals and nature. Her articles on wildlife, wild lands, backyard habitat creation, and nature education have appeared in print and online. 

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