Each year, millions of monarch butterflies travel thousands of miles across North America to escape the cold and find ...

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

Newly released data shows that the number of monarch butterflies migrating to California this winter is near-record low. "We ...

Monarch butterflies depend on human intervention to thrive in the wild, as highlighted by the traveling exhibit "Monarchs and ...

The natural phenomenon of the iconic monarch butterflies migrating south for the winter is a fascinating one - and it's one ...

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.

We know small populations are especially vulnerable to environmental fluctuations, and we think that’s what happened this ...

MADISON, Wis. — The number of monarch butterflies spending the winter in the western United States has dropped to its second-lowest mark in nearly three decades as pesticides, diminishing ...

This winter, volunteers from the Xerces Society, a nonprofit environmental group, tallied just 9,119 western monarchs — a ...

In 2023, more than 16,000 butterflies were counted at one local grove. The most recent count was a tiny fraction of that.

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

A 2,000-mile migration was thought to be a “foolish ... the USFWS issued a December 2024 proposal to list the monarch butterfly as a threatened species under the Endangered Species Act.