Study Finds That US Butterfly Populations Are Severely Declining

PORTLAND, Ore.; March 6, 2025 — 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, and it means we’ve lost more than 20% of butterflies in just 20 years,” said Collin Edwards, lead author of the study. “This is a wake-up call for the need to conserve butterflies and their habitat.”

While a number of studies have previously showed regional butterfly declines, this is the most complete – and concerning – picture of the status of U.S. butterflies. The study found ten times as many declining species as increasing species. 107 species declined by more than 50%, and 22 species declined by more than 90%.

Declines were present across all butterfly families, from the little-known sandhill skipper butterfly to more wide-spread species like the American lady butterfly.