March 2025: New Study finds that US butterfly populations are severely declining
A new study published today in Science has found that populations of butterflies across the United States are declining. In addition to dramatic declines for individual species, the study concluded that total abundance of butterflies has declined by 22% from 2000 to 2020. That means that for every five butterflies seen 20 years ago, now there are only four. “Our study found that the total number of butterflies declined by 1.3% a year. That may not sound like much, but it adds up quickly,” said Collin Edwards, lead author of the study. “This is a wake-up call for the need to conserve butterflies and their habitat.” This study is the first such comprehensive analysis of butterflies in the United States. The work was conducted by a USGS-sponsored Status of Butterfliesworking group.
 

This study has been covered in The Guardian (free) and in the New York Times (gift link) - which built a visualization tool that shows example species and their trends for any location within the study area.
 
This work would not have been possible without decades of work by the regional programs we support. Of 35 total data sources, sixteen were NABMN member networks who use the North American Butterfly Monitoring Network’s (NABMN) data management system, pollardbase.org. The North American Butterfly Association (NABA) also contributed data from its Seasonal Count program, which has also been supported through NABMN.
 
The study found ten times as many declining species as increasing species. Of the more than 300 species with enough data to estimate trends, 107 species declined by more than 50%, and 22 species declined by more than 90%. Declines were present across all butterfly families, from butterfly species including the little-known Sandhill Skipper to more wide-spread species like the American Lady. Research suggests that habitat conservation and protection from pesticides could reverse this trend for many species.