Monarchs in Search of Water at the Winter Sanctuary in Mexico

Monarch Butterflies

Monarch Migration News: February 18, 2016
By Elizabeth Howard

As temperatures rise and the air dries, monarchs move out of their clusters during the day to the delight of sanctuary visitors.

News: In Search of Water
Warm, dry weather stimulates the butterflies to move out of their colonies to find water. Mexico's dry season began when the monarchs arrived, about 4 months ago. As the air becomes increasingly dry, it dries the forest and the butterflies. The wind — and the lack of moisture in the air — dries them quickly. Dew, a reliable source of water earlier in the season, is becoming scarce.

This weekend at the sanctuary, Estela noted monarchs leaving their clusters and traveling to water.

"Monarchs keep rushing everyhere to find little ponds, streams or humid places to moisture themselves. I might dare to say this season gives the impression to be drier than those in former years. Ponds and streams are not as vigorous this year and sites for drinking seem less abundant."

Thirsty Butterflies

Moisture is Falling

Monarchs, Mountains and Moisture
By Dr. Lincoln Brower

Morning Mist Early in the morning, the mist is engulfing the butterflies and condensing on the Oyamel fir trees.

Inside the Colony Clusters of monarchs on the Oyamels are enshrouded in mist.

Taken early in the morning on 11 December 2006, this picture shows how the condensed mist freezes on the magnificent open area on Cerro Pelon, known as the Llanos de los Tres Goberonores. In this picture, you cannot see the colony, but it is all the way down at the end, to the right, in a grove of cedar trees.

Mist to Frost Taken early in the morning on 11 December 2006, this picture shows how the condensed mist freezes on the magnificent open area on Cerro Pelon, known as the Llanos de los Tres Goberonores. In this picture, you cannot see the colony, but it is all the way down at the end, to the right, in a grove of cedar trees.

Later in the morning, in the same area, we found several thousand monarchs drinking dew. The sun's rays had fallen on the frosted ground vegetation and the frost had melted into dew. The monarchs flew out of the overwintering colony to drink the dew drops.

Frost to Dew Later in the morning, in the same area, we found several thousand monarchs drinking dew. The sun's rays had fallen on the frosted ground vegetation and the frost had melted into dew. The monarchs flew out of the overwintering colony to drink the dew drops.

Drinking Dew This monarch’s proboscis is in the grass, imbibing the dew.

This monarch failed to fly back into the clusters before nightfall. Water droplets condensed on its wings. This is a very precarious situation. The dew can freeze when the overnight temperature drop below freezing. This often happens in open areas that are exposed to the cold, clear sky.

Water on Wings This monarch failed to fly back into the clusters before nightfall. Water droplets condensed on its wings. This is a very precarious situation. The dew can freeze when the overnight temperature drop below freezing. This often happens in open areas that are exposed to the cold, clear sky.

This butterfly is a victim of a freezing event and will not survive. The frost crystals mortally wounded the butterfly. They penetrated through the cuticle and disrupted the cells. Although millions of monarchs may fly out of the colony on sunny days to find water to drink, almost all of them manage to fly back into their colonies. Only a few get stranded in open areas where they may freeze to death.

Killed by Frost Crystals This butterfly is a victim of a freezing event and will not survive. The frost crystals mortally wounded the butterfly. They penetrated through the cuticle and disrupted the cells. Although millions of monarchs may fly out of the colony on sunny days to find water to drink, almost all of them manage to fly back into their colonies. Only a few get stranded in open areas where they may freeze to death.

The high altitude mountains capture moisture through a process called adiabatic condensation. As moisture-laden air rises, it expands and cools, then clouds form. At the high altitudes, the moisture condenses as water droplets on the needles of the Oyamels and pines.

Mountains Capture Moisture The high altitude mountains capture moisture through a process called adiabatic condensation. As moisture-laden air rises, it expands and cools, then clouds form. At the high altitudes, the moisture condenses as water droplets on the needles of the Oyamels and pines.

Mist on Monarchs You can see droplets of condensed mist on both the pine needles and on the butterflies.

Mexico's dry season begins when the monarchs arrive in November and lasts until they leave in March. The air becomes increasingly dry as the months go by, drying out the forest and the butterflies. Even dew becomes scarce.

Overwintering During the Dry Season Mexico's dry season begins when the monarchs arrive in November and lasts until they leave in March. The air becomes increasingly dry as the months go by, drying out the forest and the butterflies. Even dew becomes scarce.

By March, the monarch's winter habitat is extremely dry. The colonies break up as the butterflies fly out in search of water. They move down the mountain into the lower portions of the watersheds. It’s important to protect the entire watershed so monarchs can find moisture during the final weeks before spring migration.

Colony Break-up By March, the monarch's winter habitat is extremely dry. The colonies break up as the butterflies fly out in search of water. They move down the mountain into the lower portions of the watersheds. It’s important to protect the entire watershed so monarchs can find moisture during the final critical weeks before spring migration.

What does the graph reveal about monarchs and moisture?

Weekly Journal

Monarchs and Moisture at Overwintering Sanctuaries in Mexico


Conservation News: Illegal Logging Almost 25 acres of a highly critical area of the core zone of the Monarch Butterfly Biosphere Reserve has been destroyed by illegal logging, say U.S. and Mexican scientists. Satellite images reveal the destruction took place in December, 2015. "We want to emphasize that we are not assigning blame with this report, but sharing information that we hope will highlight the magnitude of the challenge that we are facing, and lead to increased protection for monarch habitat," says Dr. Karen Oberhauser. Illegal Logging in Sanctuary Core Zone

Karen Oberhauser, Lincoln Brower, Daniel Slayback, Pablo Jaramillo-López, M. Isabel Ramirez and Linda Fink

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Next Update February 25, 2016