Monarch butterfly numbers are up this year at Mexico’s largest sanctuary

Published December 19th, 2021

Monarch butterfly numbers in the El Rosario sanctuary in Michoacán are up about 30% compared to recent years, according to a sanctuary official.

The black and gold-winged insects migrate thousands of kilometers from Canada and the United States to overwintering in the oyamel fir forests of Michoacán and México state.

Marino Argueta told the newspaper El Heraldo de México that 130-150 million butterflies have reached El Rosario, located in the municipality of Ocampo.

“Millions of butterflies arrived this year and the climate … up until now has been very favorable, they’ve even come down to the sanctuary entrance,” he said.

An increase in the number of overwintering monarch butterflies has also been reported in coastal California, where the insects arrive from inland areas of the western United States.

El Rosario, which calls itself Mexico’s largest and most visited butterfly sanctuary, opened to visitors in late November and some 10,000 arrived in the first two weeks. Almost 70,000 people visited the sanctuary during the 2020-21 winter but numbers are expected to be almost three times higher this season.

Meanwhile, in the neighboring municipality of Zitácuaro, indigenous Mazahua residents of the town of Cresencio Morales have created a “forest guard” to protect the monarch butterflies’ winter habitat from illegal logging.

Groups of 20 armed residents take turns to patrol the Cresencio Morales ejido (community-owned land), part of the Monarch Butterfly Biosphere Reserve, a World Heritage site. Guards fire warning shots to let would-be loggers know they are there and that cutting down trees won’t be tolerated.

One guard told the newspaper El País that they have to carry firearms because the criminals that illegally log the forest are armed. He asserted that the government does nothing to protect the forest from illegal logging.

“We’re here to take care of our forest and we’re going to continue … until we see there’s no illegal logging,” a female guard said.

El País reported that the forest guards know the identity of the illegal loggers because they all live in the same town. However, they declined to name them or the criminal group with which they collaborate.

“La Familia Michoacana? The Jalisco cartel? They shrug their shoulders. It’s not prudent to say,” the report said.

Illegal logging, a huge problem in Mexico, and climate change were the main factors in a 26% reduction in the number of monarch butterflies overwintering in Mexico in 2020-2021, according to the World Wildlife Fund and the National Commission of Natural Protected Areas.

The Cresencio Morales ejido was identified as one of the areas most affected by illegal logging. But the forest guards are determined that won’t be the case in the future.

“What they want is our land, but we won’t allow them to have it. We’re going to defend it to the end,” one guard said.