'A cause for worry': Mexico's monarch butterflies drop by 26% in year

Butterflies had bad year after four times as many trees were lost to illegal logging and extreme climate conditions

The number of monarch butterflies that reached 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 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, according to government figures.