A recent NYT article, hopefully not behind their paywall, talks about
monarch tracking. If it is behind a paywall, you can access it via the
company's website at
https://celltracktech.com/ .
The article talks about newly available micro trackers attached to
monarchs and shows some recent results tracking butterflies from North
America to Mexico. The trackers can be purchased at Cellular tracking
Technologies, although they do state that they are intended to be used
for conservation and focused research.
The article can be accessed here:
https://www.nytimes.com/2025/11/17/science/monarch-butterfly-migration-tracking-sensor.html
Garry Kessler