Number of monarch butterflies hibernating in Mexico plunged 26% last year — and climate change and forest degradation are to blame BY LI COHEN FEBRUARY 27, 2021 / 12:40 PM / CBS NEWS Monarch butterflies provide a unique spectacle every fall as they migrate to Mexico to hibernate for the winter. But now, that migration is at risk, as logging and climate change have taken a toll on the areas where these butterflies rest. According to a new report by the World Wildlife Fund and