Researchers attach Bluetooth tags on monarch butterflies in N.B. to track migration

FREDERICTON – Researchers in New Brunswick say they are using new Bluetooth tags to track monarch butterflies on their long journey from Canada to Mexico.

Employees and volunteers from two New Brunswick-based conservation groups attached the tiny tracking tags to 22 monarchs in early September.

The solar-powered tags emit signals that can be picked up by any Bluetooth-enabled cellphones within 100 metres. 

The location of the insect is then automatically posted on the Project Monarch map, helping researchers track the monarch’s annual 4,000-to-5,000-kilometre migration to its overwintering grounds in Mexico.

Francie Morgan, a program coordinator with Nature NB, said much of the monarch migration remains a mystery and this data will help scientists better understand where the insects are stopping along their route and where they are finding shelter from storms.

Nature NB partnered with the Point Lepreau Bird Observatory on the project, which could also help the provincial government craft its plan to protect the species, which was designated as an endangered species in the province in 2022.

“If we can get a better understanding of the areas that monarchs are taking refuge … we can better protect them to be more resilient in the face of climate change,” she said.

Morgan said traditional tracking methods involve attaching visual tags to monarchs and recapturing them along their migration to record their location.

Now, researchers can see a monarch’s location more frequently, which helps fill in gaps along their lengthy journey south.

Each tag costs about $300, Morgan said, adding that the project received funding the New Brunswick Environmental Trust Fund, NB Power and Environment and Climate Change Canada.

Jim Wilson has been tagging monarch butterflies at Point Lepreau for 20 years and he said the new technology is a significant improvement.

“It’s light-years ahead because in real time, we can see where our butterflies are going,” he said. “Everybody who is following this literally is mesmerized by what we’re seeing.”

Wilson says the group has already learned something new about the monarchs they tagged.

He said the map showed that several butterflies went from Point Lepreau to Nova Scotia instead of flying south.

Wilson believes strong westerly winds may have blown the monarchs off course for a few days, but he said that they have since started making their way south again.

Morgan said they attached the tags to each monarch’s back with eyelash glue, adding that the antennas are about the length of the insect’s abdomen.

She said the tags weigh as much as a few grains of rice but are still a “notable portion” of a monarch’s body weight, which is about half a gram.

These tags are more invasive for monarchs than the traditional visual tags, but Morgan said the butterflies have responded well.

“They are incredibly resilient, and they’re using the technology like champions,” she said.

The data from the tags will also be available to scientists and conservation groups across Canada, the U.S. and Mexico, which will help them make conservation decisions moving forward, she said.

But the data isn’t just for researchers, anyone who wants to learn more about the monarch migration can track the butterflies using the Project Monarch app.

Wilson said watching each monarch’s progress is “amazing.”

“What you see here as this is unfolding is this fragile little butterfly battling the elements,” he said. “And you’re just rooting for it … you’re hoping that this little butterfly will make it.”

This report by The Canadian Press was first published Sept. 22, 2026.