California officials are begging residents to report every monarch butterfly they see as the iconic western population crashes toward collapse.
The California State Parks Foundation issued the public plea ahead of Biodiversity Day, which runs September 5 through September 13, urging residents to document any sightings through the free iNaturalist app. The group’s call for civilian scientists comes as the most recent Western Monarch Count recorded roughly 12,260 butterflies from late November through early December 2025 — the third-lowest tally since systematic tracking began in 1997.
“The data from these observations will help scientists understand where these butterflies are at different times of the year and will also help inform the upcoming 30th annual Western Monarch Count,” the foundation said in a press release announcing the citizen-science push.
The Xerces Society, which runs the Western Monarch Count, warned that the increasing frequency of record-low years signals deepening trouble for the migration’s survival. “Western monarchs numbered in the low millions regularly in the 1980s,” the organization stated. “The increasing frequency of record-low years heightens ongoing concerns about the health and stability of the western monarch migration.”
Habitat destruction, climate change, and pesticide use have driven the steep decline. The International Union for Conservation of Nature added the monarch to its Red List of Threatened Species as endangered in 2022, though the United States has only proposed listing the butterfly as threatened domestically.
A Special Status Assessment projected that by 2080, the probability of western monarch extinction exceeds 95 percent.
Participants in the Biodiversity Day observation effort need only spot a monarch, photograph it, and upload the image to iNaturalist, where the geotagged data feeds directly into scientific databases. The foundation emphasized that casual sightings matter as much as formal surveys for mapping where remnant populations persist through the year.
The 30th annual Western Monarch Count is scheduled to take place this winter across the species’ California overwintering grounds.
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