Research trip to the Monarch Butterfly Biosphere Reserve

Every November, in between the states of Michoacán and Mexico, a new generation of Monarch butterflies is born. Most of the Monarchs from Eastern North America can be found in this World Heritage Site, that stands almost 3000 meters above sea level, when millions of these butterflies convene in select small areas of the mountains. Since the temperature in these microclimates does not fall below zero, the Monarchs are able to nest for the entire winter, before starting their long journey north.   

In January and February of 2022, I visited the Monarch Butterfly Biosphere Reserve and observed students from the National Autonomous University of Mexico, like Osmar Ramirez Vasquez, who were collecting data for studies supported by Canada and Mexico. Their field work included recording hydrometric and temperature readings, compiling tree census information, and tracking colony movement.

Osmar Ramirez Vasquez with a Monarch who has been tagged by Canadian volunteers so they may follow and document their journey.

Rigoberto Martinez, from the El Rosario community, performing a complete census of Monarchs that includes the butterflies who have died due to freezing or predators as well as those still alive.

A smiling Eusebio Roldan holding the bird he rescued from thorned branches. Besides the Monarchs, the reserve hosts many other animals, including various species of hummingbirds.