Watch CBS News

Humans have officially made migratory monarch butterflies an endangered species and put them on "the edge of collapse"

Migratory monarch butterflies, known for their bright orange and spotted wings spectacularly filling the sky on a nearly 2,500-mile journey every year, are now "closer to the brink" of extinction. The International Union for Conservation of Nature announced the grim news on Thursday, saying that human activities that result in habitat destruction and climate change are mostly responsible. 

The migratory monarch is a subspecies of the monarch butterfly and is known for its annual migration from Mexico to the U.S. and Canada. Over the past decade, its population has shrunk by between 22% to 72%, depending on the measurement method used, according to the IUCN

And the majority of that decline is, the group said, is because of people. 

Logging and deforestation have destroyed substantial areas of the butterflies' winter home in Mexico and California. Last year, the World Wildlife Fund and Mexico's government issued a report that the monarch population that was in Mexico for hibernation in 2020 plunged by 26% compared to the previous year. In 2019, they had occupied nearly seven acres of Mexico's hibernation forests, while in 2020, they occupied just over five. 

The Monarch Butterfly Biosphere Reserve, where the majority of the migrating monarchs hibernate, lost a significant amount of trees leading up to the annual migration, the report found, mostly because of "clandestine" logging. 

Pesticides and herbicides also play a role in the butterflies' demise, as the chemicals kill butterflies and milkweed, which is essential for butterfly larvae to develop. In February, the U.S. Fish and Wildlife Service proposed adding prostrate milkweed to the endangered species list, saying that humans have depleted the resource through root-plowing, border security activities and construction. 

And then, of course, there is human-caused climate change. The intense droughts that have been ravaging the West Coast limit the ability for milkweed to grow. And paired with the extreme heat that dozens of states are facing, particularly California, it has created wildfires that further destroy essential plants that feed and house the species. 

While migrating monarch populations have declined from coast to coast, it's the western population that has felt it the worst, the IUCN said. The population is estimated to have declined by 99.9% between the 1980s and 2021 – from 10 million to less than 2,000. These numbers have the group concerned as to whether there are enough butterflies to prevent total extinction. 

IUCN member Anna Walker, who led the assessment, said in a statement that it's difficult to watch the species "teeter on the edge of collapse." 

"But there are signs of hope," she said, noting that organizations are working to restore habitats, plant milkweed and reduce pesticides. "...We all have a role to play in making sure this iconic insect makes a full recovery." 

The IUCN's Red List names 41,000 species that face extinction. 

Also added to the red list on Thursday are every single species of sturgeon. The IUCN found that 
"100% of the world's remaining 26 sturgeon species are now at risk of extinction." One species, the Yangtze Sturgeon, is officially extinct in the wild, and the Chinese Paddlefish, is completely extinct. 

Tigers, on the other hand, have increased by 40% since they were last assessed in 2015. They are still endangered, but the IUCN said the trend indicates that "recovery is possible." 

View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive reporting.