Tiny Trackers Helping Monarch Butterflies Recover

Got story updates? Submit your updates here. ›

A revolutionary new tracking device using tiny solar-powered Bluetooth transmitters is helping researchers and volunteers better understand and protect the migration patterns of monarch butterflies, whose populations have plummeted since the 1980s. The 60-milligram "BlūMorpho" transmitters can be attached to monarchs with little impact on their flight, allowing their journeys to be tracked in real-time by a network of crowd-sourced smartphone users.

Why it matters

Knowing the precise migration routes taken by monarchs will allow conservationists to cultivate critical milkweed and nectar plants along those paths, as well as designate more protected refuge areas, in an effort to restore monarch populations to their previous hundreds of millions of individuals.

The details

The new tracking technology represents a major advancement over previous monarch tagging efforts, which only provided data on the start and end points of migrations. The lightweight BlūMorpho transmitters can be attached to monarchs using eyelash adhesive, allowing their full journeys to be monitored in real-time by volunteers with the "Project Monarch Science" smartphone app. In a successful proof of concept in 2024, a monarch named Lionel was tracked from New Jersey to Florida, paving the way for hundreds more transmitters to be deployed across the Eastern U.S. and Canada last fall.

• In 1992, the nonprofit Monarch Watch began tagging more than 100,000 monarchs annually before their southbound migrations.
• In November 2024, a monarch named Lionel was tracked in real-time from Cape May Point, New Jersey to Florida, demonstrating the new tracking technology.
• In the fall of 2025, hundreds of BlūMorpho transmitters were deployed on monarchs leaving from across the Eastern U.S. and Canada, with thousands of volunteers now tracking their migrations.

What they’re saying

What’s next

With the new real-time tracking data, conservationists hope to cultivate more milkweed and nectar plants along the monarchs' migration routes, as well as designate additional protected refuge areas, in order to help restore their populations.