Monarch butterflies down 26% in Mexico wintering grounds

Phys.org reports, "The number of monarch butterflies that showed up at their winter resting grounds in central Mexico decreased by about 26% this year, and four times as many trees were lost to illegal logging, drought and other causes, making 2020 a bad year for the butterflies.

"The government commission for natural protected areas said the butterflies' population covered only 2.1 hectares (5.2 acres) in 2020, compared to 2.8 hectares (6.9 acres) the previous year and about one-third of the 6.05 hectares (14.95 acres) detected in 2018.

"Because the monarchs cluster so densely in pine and fir trees, it is easier to count them by area rather than by individuals."

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