Exploring the Monarch’s Winter Habitat Backyard Observation Reveals a Clue Did you notice? Frost is on the grass in the foreground. You can see dew in the distance. When the sun's rays hit the frost, it melts and becomes dew. When the frost melts... ...it becomes dew.   Dew can be important for thirsty monarch butterflies.      Dr. Calvert's Observation in Mexico: "In the early mornings, butterflies pour into the fields to drink. I have noticed that they concentrate on the sunny side of a shaded patch. They are clustered in a narrow band only 1-1.5 meters wide. "They're drinking dew there, just before it evaporates in the strong tropical sun. The monarchs can't seem to function well in the shade, so they move in this narrow band of sunshine where the sun hasn't evaporated the dew yet. "By noting whether dew or frost is present, we know if this important source of water was available to the monarchs that day. As the dry season progresses, the dry air dries out the forest and the butterflies. The wind, and the lack of moisture in the ambient air, dries them quickly. Dew is often no longer available. The monarchs have to go down to streams (and to nectar, if available)."     Copyright 2005 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form