Monarch butterfly numbers at Mexico’s largest sanctuary are up about thirty percent compared to recent years | Polarbear | NewsBreak Original

Millions of monarch butterflies in the eastern United States and Canada migrate to El Rosario sanctuary in Michoacán state each fall to overwinter, clustered together in high-elevation oyamel fir forests. They gather in about 12 colonies in the sanctuary, which have numbered as high as 380 million butterflies in 1997 and as low as 14 million in 2014.

Source: Monarch butterfly numbers at Mexico’s largest sanctuary are up about thirty percent compared to recent years | Polarbear | NewsBreak Original