Environmental News Network - Western U.S. Monarch Butterfly Population Declined Sharply in 2018

Details: By Yale Environment 360; 09.Jan

California’s population of monarch butterflies declined 86 percent in 2018 compared to the previous year, according to the Xerces Society for Invertebrate Conservation, a nonprofit group that conducts an annual survey of the species in the western United States. Overall, the state’s monarch population has declined 97 percent since the 1980s.

Mohammad Munshed

California’s population of monarch butterflies declined 86 percent in 2018 compared to the previous year, according to the Xerces Society for Invertebrate Conservation, a nonprofit group that conducts an annual survey of the species in the western United States. Overall, the state’s monarch population has declined 97 percent since the 1980s.

While many North American monarchs travel to an overwintering site in Mexico, tens of thousands of others spend the cold season in California, hunkered down in eucalyptus trees. The Xerces Society estimates that fewer than 30,000 butterflies will overwinter in the state this year. This is compared to more than 192,000 butterflies in 2017, more than 1 million in 1997, and at least 4.5 millionin the 1980s.

Magazine menu

Western U.S. Monarch Butterfly Population Declined Sharply in 2018