Monarch Butterfly departure continues from overwintering sites in Mexico

[Donkees]

5. Migration Map:

Eastern North American Population
Overwintering in Mexico
The eastern population of North America’s monarchs overwinters in the same 11 to 12 mountain areas in the States of Mexico and Michoacan from October to late March.

Monarchs roost for the winter in oyamel fir forests at an elevation of 2,400 to 3,600 meters (nearly 2 miles above sea level). The mountain hillsides of oyamel forest provide an ideal microclimate for the butterflies. Here temperatures range from 0 to 15 degrees Celsius. If the temperature is lower, the monarchs will be forced to use their fat reserves. The humidity in the oyamel forest assures the monarchs won’t dry out allowing them to conserve their energy.

https://www.fs.usda.gov/wildflowers/pollinators/Monarch_Butterfly/migration/index.shtml