A beloved visitor to summer gardens is officially an endangered species.

The migratory monarch butterfly—the iconic subspecies common to North America—was declared endangered today by the International Union for the Conservation of Nature (IUCN), the global leading authority on the status of biological diversity.

The threat to monarchs comes from a combination of factors. Habitat destruction over decades in migratory monarchs’ wintering grounds has taken a massive toll. The impact is felt by both the western population, which is found west of the Rocky Mountains and winters on the California coast, and the eastern population, which is found in the eastern U.S. and Canada and winters in Mexico’s fir tree forests. In summer habitats, pesticides used in agriculture have killed monarchs and also milkweed, the plant they lay larvae in. Climate change, too, is an increasing threat as dramatic weather events such as hurricanes and drought become more common along the butterflies’ southern migration routes.

The western monarch population, less studied and more at risk, has plummeted 99.9 percent in recent decades, from around 10 million in the 1980s to just 1,914 in 2021, according to the IUCN. The eastern population declined by 84 percent between 1996 and 2014.

Monarch Butterflies have long been one of the first insects schoolchildren learned about. Along with bees, I imagine. I find it difficult to imagine what my childhood would have been like absent their beauty.