A company that makes tracking devices used by #wildlife biologists has miniaturized their design. The solar powered radio tag weighs only 60 mg and is small enough to be attached to the thorax of a monarch #butterfly. They have followed 400 butterflies migrating from places like Ontario to Mexico. #ProjectMonarch
https://www.nytimes.com/2025/11/17/science/monarch-butterfly-migration-tracking-sensor.html