The migratory route of the monarch butterfly towards Mexico has already been activated this fall. The program Royal Mail of PROFAUNA confirmed the first records on its journey from the United States and Canada to the forests of the center of the country, marking the start of the 2025-2026 season.
According to community monitoring, the October 11 solitary individuals were detected in Coahuila and the metropolitan area of ​​Monterrey; as of October 18, a cold front from the north drove more sightings and the October 19 were reported hangers In northern Coahuilense. More than 20 butterflies were observed grouped together at the La Amistad Dam, and two days later, the count exceeded 90 copies at that very point.
Dates and countdown: This is how the season started in the north
Reports validated by citizens and volunteers Royal Mail describe increasing traffic throughout the week of October 18, with small groups in flight encouraged by the northern winds. The first nighttime concentrations were located in trees near bodies of water, a common pattern when weather conditions change.
In addition to the La Amistad Dam, on a ranch in the municipality of Guerrero Six monarchs were recorded perched on a huizache. With the consolidation of these resting places, the technical team formally started the phase of passing through Coahuila, key to keeping the environmental monitoring of migration.
A strategic corridor for biodiversity
Coahuila is located in a strategic point of the journey that millions of monarchs travel from the north of the continent to the fir and pine forests from central Mexico. As they pass, the butterflies act as natural pollinators, contribute to the genetic diversity of plants and function as health indicators of the ecosystems.
The cold fronts Coming from the north, the birds tend to organize the migration, favoring nocturnal gathering in safe, wooded areas. This behavior allows for more precise location of the birds. hangers and, at the same time, evaluate the environmental conditions during transit.
Cultural calendar: when science meets tradition
The massive arrival usually coincides with the dates of the Day of the Dead, between the end of October and the beginning of November, when numerous communities of Michoacán and the State of Mexico They associate the monarch with the symbolic return of loved ones. Every autumn, the sky is tinged with orange and black and nature becomes part of the collective tribute.
Last season, the presence of the species almost doubled compared to the previous cycle: it was estimated 1,79 hectares occupied in eight colonies. According to CONANP and WWF Mexico, three colonies were located in Michoacán and five in the Estado de México, with three inside the Monarch Butterfly Biosphere Reserve and five outside the protected area.
Among the records, the colony of Atlautla (Edomex), with 0,098 hectares. Historical data recall a minimum of 0,67 hectares in 2013-2014 and a maximum of 18,19 hectares in 1996-1997, figures that help to measure the interannual variability of the phenomenon.
Conservation and citizen participation
Authorities and organizations recommend reduce the use of pesticides In transit areas, respect rest areas and avoid disruptions during the flight. Local collaboration is key to ensuring clean habitats with available nectar and connectivity between vegetation patches.
The report of sightings with photographs and location to programs such as Correo Real improves the quality of monitoring. It is also suggested to promote the milkweed planting in suitable areas, an essential plant for the life cycle of the species, and drive with caution on roads where the transit of butterflies may be significant.
With the first counts confirmed and established perches in the north, everything points to a sustained advance towards the sanctuaries in the center of the country in the coming weeks. The phenomenon combines ecological and cultural value, and its coordinated monitoring will allow us to better understand how climate and landscape influence one of the most emblematic migrations in the hemisphere.
