Monarch butterflies previously considered Threatened, have now been classified as Endangered by the International Union for Conservation of Nature, the world’s most comprehensive scientific authority on the status of species. Two major driving factors are habitat loss (and thus, food loss), and climate change.
“The numbers of Western monarchs, which live west of the Rocky Mountains, plummeted by an estimated 99.9 percent between the 1980s and 2021. While they rebounded somewhat this year, they remain in great peril. Eastern monarchs, who make up most of the population in North America, dropped by 84 percent from 1996 to 2014. The new designation of endangered covers both populations.” (New York Times.)