Experts say the population of monarch butterflies wintering in central Mexico is up 144 percent over last year.
A Mexican government statement says the butterflies are occupying 14.95 acres in the mountains of Michoacan and Mexico states. That’s an increase from 6.12 acres a year ago.
Millions of monarchs migrate from the United States and Canada each year to pine and fir forests to the west of the Mexican capital.
They arrive in such numbers that their population is measured by how much surface area they cover.
Wednesday’s statement says this year’s is the biggest measurement since the 2006-2007 period. A low of just 1.66 acres (0.67 hectares) was recorded in 2013-2014.