Letter from Estela Romero: Holding Our Breath — Awaiting the Massive Departure of Monarchs


Published: 03/16/2022

Dear friends,

In mid-March temperatures at monarch butterfly sanctuaries can reach 26 Celsius. In these high elevation mountains, the monarchs have hibernated in the Oyamel fir trees – but now they are on the move. 

For several weeks, monarchs have gradually been departing from the Cerro Pelon and Sierra Chincua Sanctuaries. Monarchs in the El Rosario Sanctuary have departed in lower numbers. But now we see an increase in numbers of departing monarchs. Big transformations are happening. 

El Rosario Sanctuary

The large and heavy clusters covering the Oyamel fir trees over the winter have now dispersed. Very few orange sparkles on the trunks of trees remain. This week, monarchs have formed a seemingly endless rushing parade along every trail and path in El Rosario Sanctuary. Monarchs still search out cooler shelter to rest and refuel before the journey north.

La Salud Ejido

La Salud, a neighboring Ejido, is located just north of El Rosario Sanctuary. A significant number of monarchs have now moved to the La Salud forested area, following a pattern that has emerged over the last 4-5 years. Monarchs make their last, massive halt before their final departure. A stream runs through La Salud forest providing needed water for thirsty monarchs. The shade provides shelter from the March sun which appears to be hotter than normal.

Sierra Chincua Sanctuary 

While this important move has been taking place, the second largest colony located in the Sierra Chincua Sanctuary is also experiencing changes. Located about 10 kilometers north of the El Rosario Sanctuary, monarch numbers have increased. Monarchs will move even higher into the mountains of Sierra Chincua before journeying north. 

Mating activity has been increasing at all the sanctuaries.

Breaking News – As of Monday, March 14, 2022

After days of conducting an exhaustive search, the Ejidatarios at Sierra Chincua Sanctuary announced the official departure day. Thursday, March 10, 2022, is the official registered day of the final massive departure at this colony. 

Minor numbers of monarchs remain at Cerro Pelon and Sierra Chincua Sanctuaries.

With temperatures rising, we all await for the final massive departure which should happen any day now. We will continue to monitor movement from the largest southern colony at the El Rosario Sanctuary and at the La Salud forested area. temperatures showing their amazing resilient condition. 


The monarch tagging program continues to be an extremely important research program. The tagging helps establish where monarchs originate in the north that reach the overwintering sites in Central Mexico. Tagging also helps establish the timing and pace of the migration as monarchs moved south. 

Monarch Watch Conservation Specialists have visited several locations: El Rosario, Sierra Chincua, Cerro Pelón and Piedra Herrad. They have collected hundreds of tags from Ejidatario guards in the sanctuaries. This is a great example of cooperation among organizations and community members. 

We await for the official population numbers as we also await the final massive departure to happen.

Estela Romero

Angangueo, Michoacán, México.


Note to our readers: This article has been edited from the original English version for clarity.

Read the Spanish version of Estela Romero’s letter»