In fall 2025, approximately 470 Monarchs in the eastern U.S. were deployed with Blu+ transmitters. Of those that made it to Mexico and spent the winter there, female monarch XSTI009 (where the X stands for Xerces) appears to be the first to make it back to the United States, flying an incredible 320 miles in just one day.
Eastern Monarchs
With Upgraded Transmitters, We Can Now Track Migrating Monarchs Better than Ever
Xerces has been helping to test these new tags for over a year, and we are excited to finally put them into widespread use.