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News: Population Trends

Eastern Monarch Overwintering Population Numbers Announced

The monitoring report of the forest area occupied by monarch butterflies in 2017-2018, carried out by WWF and CONANP, registered 2.48 hectares of occupied forests, an area that represents a decrease of 14.77 percent from last year.  Read More »

Western Monarch Butterflies Continue to Decline

Annual census of monarchs overwintering on the California coast reveals the lowest number of butterflies in recent years.  Read More »

Estimating the Number of Overwintering Monarchs in Mexico

Every year we anxiously await news of the monarch overwintering population count from Mexico. When are they done and how are the monarchs counted?  Read More »

Measuring Monarchs and Milkweed

Monarch population size estimates allow us to assess the status of the population, and set goals for restoring it to a sustainable level. Monarchs’ declining numbers have gained a lot of attention, but how is the monarch population measured anyway?  Read More »

Eastern Monarch Population Numbers Drop 27%

This year’s measurement of the eastern monarch overwintering population showed a 27% decrease compared to last year, occupying 2.91 hectares of forest in Mexico’s transvolcanic mountains during the winter of 2016-17.  Read More »