photo by: Shawn Valverde

A monarch butterfly with a tag on its wing perches on a flower head at Monarch Watch's butterfly tagging event at the Baker Wetlands on Saturday, Sept. 21, 2024.

Monarch Watch is contributing to a comprehensive study of the Monarch butterfly migration by tracking butterflies with tiny solar-powered radio tags, revealing new insights into their long journeys across North America.

Monarch Watch is a nonprofit education, conservation, and research organization founded in 1992 based at the University of Kansas. The organization focuses on the monarch butterfly, its habitat, and its fall migration. It operates a large-scale citizen science tagging program to track migration and a “Monarch Waystation” program to create, conserve, and protect habitat for monarch butterflies.

In fall 2025, Monarch Watch began participating in the Project Monarch Collaboration – as part of 25 other organizations – to deploy BlūMorpho radio tags. The Project Monarch Collaboration was founded through a partnership between Cellular Tracking Technologies and the Cape May Point Arts and Science Center, and according to a press release, it’s the most comprehensive tracking study of monarch butterfly migration ever conducted.

The Monarch butterfly follows two main migration paths in North America. The larger eastern population breeds across southern Canada and much of the United States, then travels thousands of miles south each fall through the central U.S. to wintering forests in Mexico.

A smaller western population breeds in the western U.S. and migrates shorter distances to coastal overwintering sites in California. In spring, successive generations move north again, using cues like the sun’s position, internal timing, and geographic features to navigate.

In Kansas, monarch butterflies are most commonly seen during two periods of the year. They typically begin returning in mid-May, when smaller numbers move north to breed and lay eggs on milkweed. The best time to see large numbers is during the fall migration, especially from mid-September into early October.

The BlūMorpho tags are lightweight, solar-powered radio tracking tags applied with eyelash glue and attached to the thorax of Monarchs. Even though the tags are the size of a grain of rice, they provide lots of tracking data for each individual monarch butterfly.

Once deployed on a monarch, the tags use Bluetooth crowd-sourced location networks to increase the number of detections. These updates show more precise locations in near-real time during a monarch butterfly’s journey, both during the fall migration as well as northbound movement in spring.

All of the project’s partners have deployed more than 600 BlūMorpho solar-powered radio transmitters this migration season, including more than 500 during the fall 2025 migration and at least another 150 ahead of the spring 2026 migration. In September 2025, Monarch Watch deployed 30 BlūMorpho tags on migratory monarch butterflies.

“Ours hung around for quite a while,” Monarch Watch Director Kristen Baum said. “The winds were blowing in the wrong direction … So we were kind of wondering if something happened with the tags.”

However, she said what was super interesting was getting to see all of the Monarch butterflies that were tagged moving up north for the spring.

“You got to see these paths coming from different areas and different timings,” Baum said. “And then watch the trip to the overwintering sanctuaries in Mexico. And so we’ve seen some of those that were tagged in the fall are moving north. But, of course, we’ve lost a lot along the way. Survival is not great during the fall migration. Of course, we’ll have a better idea of what that looks like now with BlūMorpho data.”

Baum said one of the 150 butterflies tagged in Mexico actually made it to Texas on Tuesday, the first tagged butterfly to hit the states. The butterfly was released on Feb. 21, and before this week, was last detected on March 3.

“So somehow it missed being detected for 533 miles, but it was super exciting,” Baum said.

Even though Monarch Watch has been tagging butterflies for decades, Baum said when working with an organism that has such a wide geographic range, the thought of having to do an effort like this on its own would be impossible.

“One of the reasons that the Monarch Watch tagging program and all the community interest and support and involvement has worked so well (is because) there’s lots of interest, and it takes lots and lots of people to make that work,” Baum said. “I think the same can be said for the project.”

Baum said the best way the community can support Monarchs is getting as much habitat out there as possible.

“This past year, the migration was pretty late, so having good nectar sources that are blooming later in the year, having good nectar sources that will bloom when you have really dry conditions,” Baum said. “There’s also been years where we’ve had flooding. You’ve got to hit all of the extremes, so thinking about having resources available no matter what the year brings.”

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To track the paths of these Monarch butterflies, people can download the free Project Monarch Science app in their device’s app store.

The app is organized into two main sections: Detect and Data, each offering different features and information.

In the Detect section, a device can be used to start and stop scans for tagged monarch butterflies in the surrounding area. Any tagged monarchs detected during a scan appear in a list on the screen. These detections can then be uploaded to the Project Monarch database.

And in the Data section, several tools and views are available. There is a list of individual tagged monarchs which people can see with the butterfly icon, a map showing the most recent locations of all tagged monarchs with the map icon, and leaderboards highlighting the highest number of unique monarchs detected with the trophy icon. There is also a list of the highest total number of detections which can be viewed by clicking on the people icon.

From the monarch list, specific tagged butterflies — such as Monarch Watch tags labeled “MW” — can be searched. Selecting an individual monarch opens its profile, where details such as sex, release date, most recent detection date, and distance traveled from the release point are displayed. A map view can also be toggled to show the monarch’s last recorded location.