The annual Western Monarch Count observed a peak population of 9,119 Monarch butterflies in California this winter, marking a sharp decline in the last few years.
The count, administered by the Xerces Society for Invertebrate Conservation, is the second-lowest total since the program began in 1997. In 2020, less than 2,000 were observed.
More than 200,000 were observed each year from 2021-2024, making the sharp dropoff worrisome to conservationists.
“The population’s size is extremely concerning,” said Emma Pelton, an endangered species biologist with the Xerces Society for Invertebrate Conservation. “We know small populations are especially vulnerable to environmental fluctuations, and we think that’s what happened this year. The record high late summer temperatures and drought in the West likely contributed to the significant drop-off we saw in the third and fourth breeding generations.”
A site in Santa Barbara, owned by The Nature Conservancy, had more than 33,000 monarchs last winter. This year, it had just 198.
Extinction for the Western Monarch butterfly has a 95% chance of happening by 2080, according to the U.S. Fish and Wildlife Service. The service has proposed that the monarch butterfly be listed federally as an endangered species.
“A lot of people care about monarchs. Voluntary efforts like pollinator gardens and restoring habitat are probably a reason they aren’t in worse shape,” said Isis Howard, coordinator of the Western Monarch Count with the Xerces Society. “However, these actions are not enough. To help monarchs recover, we need to work at a larger scale and address widespread issues like pesticide contamination and climate change that are beyond what voluntary efforts have been able to achieve.”
