Monarch Tagging: How Did We Get Here and How Can You Participate?

A monarch butterfly sips on the nectar of common milkweed.

No other species seems to have captured the public’s interest quite like the monarch butterfly (Danaus plexippus). With their striking orange and black coloration, impressive natural history and epic migration, there is no wonder why we are drawn to this amazing creature.

The Mystery of Missing Monarchs

For years in their northern range, monarchs were spotted during the summer months and then as winter neared, there was simply no sign of them anywhere. Most butterflies could be found overwintering as eggs or pupa, but not monarchs. There was also no evidence they spent the winter under the bark or in crevices, as do the mourning cloaks.

Monarch tagging
A tagged monarch butterfly at Farbach-Werner Nature Preserve. (Photo: Stephanie Morris)

As we humans are curious by nature, it’s no surprise that several scientists wanted to solve the mystery of these missing monarchs. Scientists noted that physiological changes appeared in monarchs hatched during the fall. These butterflies had larger wings, did not appear to reproduce and seemed to congregate and move in a southward direction. And so, the question arose: Could these insects be migrating?

Monarch tagging involves placing a paper sticker on a monarch’s wing. The stickers are lightweight that they do not affect flying. (Photos: Stephanie Morris)

One Canadian scientist took an incredible interest in solving this mystery. Fred Urquhart immediately began formulating a plan to track these animals to discover where they were going. The challenge was to find a tracking mechanism that was permanent enough to survive the journey, yet lightweight enough to not hinder the butterfly’s flight. By the early 1940s, he had developed a paper sticker that would adhere to the wing and allow for flight. Realizing just how massive of an undertaking this project would become, the husband and wife team of Fred and Norah Urquhart realized they’d need help. Together, in 1952, they published an article in Natural History asking for citizens to join in the endeavor. They began sending tags to interested individuals throughout the monarch’s range so that they could increase their chances of finding the monarch’s winter destination.

While much had been learned about the monarch’s natural history, little headway had been made on solving the mystery of migration for close to 20 years. In 1970, the Urquharts, once again, put out many publications laying out their successes to this point and asking for involvement from the public. With that, thousands of people across Canada, the United States and Mexico joined forces in the hunt for the elusive overwintering grounds.

The first tagged monarch recovered at the overwintering grounds was tagged in Chaska, Minnesota.
The first tagged monarch recovered at the overwintering grounds was tagged in Chaska, Minnesota. (Map courtesy

With a great increase in tagged butterflies and more awareness of the task, the overwintering ground was discovered in 1975 with the help of Cathy and Ken Brugger, two citizen scientists in Mexico that had found themselves right in the middle of the overwintering grounds and reached out to the Urquharts. The story goes: When Dr. Urquhart was finally able to visit the site, one branch above him became so heavy with butterflies that it broke and crashed to the ground. When he looked down, he was surprised to see one of the tags from his very own project. That single butterfly was tagged in Minnesota and had made the incredible journey all the way to a mountaintop in Mexico!

The discovery of the overwintering ground was announced in the August 1976 issue of National Geographic.
The discovery of the overwintering ground was announced in the August 1976 issue of National Geographic. (Image courtesy

In August of 1976, Cathy Brugger was featured on the cover of National Geographic, where the news was revealed to the world. Finally, after 30 years of research, the mystery had been solved. We now knew that a single monarch could travel around 2,000 miles to reach the overwintering grounds near Mexico City. While this discovery was exciting, it was only the beginning of solving the mystery of the monarchs. How could an insect make such an incredible journey? What triggers migration and the seasonal physiological changes to prepare for it? Are there other overwintering grounds yet to be discovered? How could an individual that was hatched in Ohio possibly navigate to such a specific location?

While some of these questions have been answered, there are many more that have not. It is only through continued citizen science activities that we will grow our understanding of this unique species. As these butterflies often travel through three countries, it is only through large-scale efforts and citizen science opportunities that we can truly answer many of these questions. Monarch tagging is an easy activity to do with a class, scout group, garden club or even in your own backyard. If you want to be take part, tags can be purchased at, or check our calendar for monarch tagging programs each fall where you can get hands-on experience with Great Parks interpreters.

Who knows? Maybe you’ll tag the next butterfly that leads to an exciting new discovery!

Stephanie Morris
Nature Interpreter, Farbach-Werner Nature Preserve