Letter From Estela Romero: Focus on El Rosario Sanctuary

Greetings Friends,

Concerning Behavior Continues

After a couple of weeks with only intermittent weak sunshine and below zero temperatures overnight, days now come back to sunny, warm and only mild frost conditions at night. At the increase of temperatures this weekend, monarchs present such a concerning restlessness both around the forest and flying far downhill, as if it were mid-to late February.

Update-El Rosario Sanctuary

With colonies presumably having defined their densities and locations for early winter, one observes that the area now occupied by monarchs in the El Rosario Sanctuary, which typically is home to the largest overwintering colony, shows a beautiful but smaller area of occupation.

The area of occupation seems substantially smaller than last year. One can see this colony within only a short walk which is unlike what we are used to observing in this Sanctuary. We are feeling uncertain. We wonder if we may still see a sudden increase in numbers. Perhaps this could still happen.

A Source of Life Giving Water

Springs and streams can be found throughout the Oyamel fir forests of the Monarch Butterfly Biosphere Reserve. Monarchs rely on these water sources for moisture. Monarchs cannot land on open water so these shallow streams and springs provide perfect spots for monarchs to sip water while perching on dry rocks, leaves or muddy soil clumps. This strategy is called “puddling” and allows monarchs to not only obtain moisture but also minerals and salts.

Monarchs are not the only ones who benefit from these springs. The Oyamel fir forests of this region are major watersheds for central México. Two main central rivers, the Balsas River and the Lerma River, are the main water supply for México City and surrounding towns. This water system is known as the impressive Cutzamala water complex, bringing water to over 25 million people as far as up to 120 kilometers distance.

Springs, located throughout the monarch overwintering forests, supply a constant flow of water to fill damns and rivers from where the Balsas River forms and pours down waters of unique composition and pureness.