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 habitat and climate ...

The study was one of several that assessed the effects of climate change on three species of butterflies whose populations are declining.

Before National Geographic published its famous August 1976 cover story detailing the search for the monarch butterfly’s wintering grounds, nobody knew where these strikingly beautiful creatures ...

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 habitat and climate ...

The number of monarch butterflies in California is in sharp decline this year, and biologists say record-high late summer temperatures and drought in the west likely contributed to the dropoff.

ST. LOUIS COUNTY, Mo. – Say the word “butterfly,” and the iconic orange and black of the monarch may immediately spring to mind. But they are becoming a rarer and rarer sight in nature.

The number of monarch butterflies spending the winter in the western United States dropped dramatically this year even as federal officials move to extend protections for the beloved pollinator ...

The Western population of the monarch butterfly has declined to a near-record low with fewer than 10,000 found living in California this winter, a foreboding sign for the future of the beloved ...

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 habitat and climate ...

FILE - A butterfly sits on a leaf at Monarch Grove Sanctuary in Pacific Grove, Calif., on Nov. 10, 2021. (AP Photo/Nic Coury, File) ...