Data story 08 ยท Tracking
Following one monarch at a time
Tiny solar radio tags now let scientists follow single monarchs. In September 2025, 30 monarchs were tagged at Long Point, Ontario, and their signals were picked up as they flew south. We are asking for permission to show the real tracks here.
Read it right
Every chart has limits. Here is what this one can tell you, and what it cannot.
What this shows
- A trip at monarch paceThe straight line from Long Point to the winter forests, flown at about 44 km a day, with sourced facts along the way.
- Public facts about the tagsWhat the radio tags are, and the Long Point monarchs that carried them.
- The distance to MexicoHow far Long Point is from the winter forests in a straight line.
- How tracking grewFrom a 2017 prototype to more than 600 tags in the 2025-26 season.
What it does not show
- The real flight pathsReal monarchs do not fly a straight line, and they go around the Gulf of Mexico. The real tracks belong to the researchers; we will add them only with permission.
- Tag recoveries as routesA Monarch Watch recovery marks where a tagged monarch was found, not the path it flew.
Sources. Xerces Society press release (17 November 2025); Monarch Watch, Radio Tagged Monarchs 2025-2026. Project Monarch is led by the Cape May Point Arts and Science Center and Cellular Tracking Technologies. Facts along the line: Parks Canada; Brower and others 2006; Gibo 1981, Canadian Journal of Zoology; Journey North. Pace: Monarch Joint Venture (40 to 48 km a day). The narrated tour is read by an AI voice (OpenAI gpt-audio, via OpenRouter) from the captions you see. See Data and credits. No endorsement implied.