"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 habitat and climate change take their toll on the beloved pollinator. ...

Monarch butterflies, known for their distinctive orange-and-black wings, are found across North America. Monarchs in the eastern United States spend their winters in Mexico and are counted by the World Wildlife Fund, which has yet to release data for this year. Monarchs west of the Rocky Mountains typically overwinter along the California coast.

The Xerces Society for Invertebrate Conservation has been counting western overwinter populations along the California coast, northern Baja California and inland sites in California and Arizona for the last 28 years. The highest number recorded was 1.2 million in 1997. The organization announced Friday that it counted just 9,119 monarchs in 2024, a decrease of 96% from 233,394 in 2023. The total was the second-lowest since the survey began in 1997. The record-low was 1,901 monarchs in 2020.

The survey noted that a site owned by The Nature Conservancy in Santa Barbara that saw 33,200 monarchs last winter hosted only 198 butterflies this year."

Todd Richmond reports for the Associated Press February 4, 2025. [2]