Painted lady butterflies are world travelers. The ones we encounter in Europe fly from Africa to Sweden, ultimately returning to areas north and south of the Sahara.

Just over 9,000 monarchs were counted in California last winter, the second lowest ever since the annual count began in 1997 ...

Monarch butterflies in the western U.S. have dropped to just 9,119 this year. In 2023, the count was 233,394, meaning a 96% decline.

The findings challenge previous assumptions about butterfly migration and highlight the role of phenotypic plasticity.

The number of monarch butterflies spending the winter in the western United States dropped dramatically this year ...

Not that long ago, monarch butterflies used to migrate in droves. However, over the last few decades, the number of these ...