North America’s monarch butterfly, whose showy looks and extraordinary migration have made it one of the continent’s most beloved insects, has been classified as endangered by the International Union for Conservation of Nature, the world’s most comprehensive scientific authority on the status of species.
The decision comes after decades of falling populations driven by losses in the plants they need as caterpillars and in the forests where adults spend the winter, combined with climate change, the assessment found. The authors reviewed about 100 studies, interviewed experts and applied criteria from the group’s Red List of Threatened Species to come up with their decision.
https://www.nytimes.com/2022/07/21/climate/monarch-butterflies-endangered-iucn.html