Millions of monarch butterflies (Danaus plexippus) roost on the Sierra Chincua (Chincua mountain) near Angangueo, Mexico. This is one of five wintering roosts for monarchs, where the cool mountain climate slows their metabolism enough for them to overwinter before migrating back northward in the spring. Logging threatens this spectacle: already one of the five sites is no longer used by the butterflies due to the forest being cleared.

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