Editorial Team Good news for the Western monarch: early 2026 counts show the overwintering population has climbed past 300,000 across California. It’s a huge rebound from the desperately low numbers we’ve seen recently, giving us some hope for the monarch butterflies and their incredible global migration. The big question now is whether this recovery can hold up against constant threats like climate change and habitat loss.
Key Takeaways
- The 2025-2026 overwintering count for Western monarchs in California is over 300,000, a massive jump from the brink of extinction just a few years ago.
- Planting native milkweed and nectar flowers is a proven strategy. These plants provide the fuel and nurseries monarchs need to complete their migration and reproduce.
- Wildfires and unpredictable weather, driven by climate change, are the biggest dangers to the monarch’s breeding and overwintering grounds, as seen in the destructive California fire seasons of the early 2020s.
- Data from volunteers in programs like the Xerces Society’s Western Monarch Thanksgiving Count is what lets us track these population changes and figure out what’s working.
- The single most effective thing individuals and communities can do is create “milkweed corridors”, continuous habitat along migration routes, to support the monarch’s long journey.
Context and Background
For a while there, things looked grim. The Western monarch population absolutely cratered, dropping from millions of butterflies in the 1980s to a terrifying low of fewer than 2,000 in 2020. That kind of collapse got everyone’s attention, sparking a huge push in conservation. The annual Western Monarch Thanksgiving Count, which the Xerces Society for Invertebrate Conservation organizes, has been our main tool for watching this unfold, and their early numbers for the 2025-2026 season show a third straight year of growth. It’s good news, but the population is still fragile.
These butterflies are famous for their marathon migration, a multi-thousand-mile trek from their breeding grounds all over the western U.S. down to very specific spots on the California coast. They target groves of eucalyptus and Monterey cypress for the winter, a journey dictated by some amazing internal GPS. When a population like this starts to fail, it’s a sign the whole system is in trouble, because their health is a direct readout of the health of the land they travel through. A U.S. Geological Survey (USGS) report confirmed what many suspected: decades of habitat destruction and pesticide spraying have been killing them off at every stage of their lives.
“The Pacific can be likened to someone "burning with fever", says Ana Liza Solis, head of climatology at the Philippines'. National weather bureau. "It can go into convulsions soon,”
Implications for Global Ecology
Seeing the Western monarch bounce back shows that focused, well-funded conservation work can actually pull a species back from the edge. Monarchs aren’t just pretty, they’re pollinators, and their work helps keep plant communities healthy along their entire migration route. The recovery is a direct result of people getting their hands dirty. We’re talking about the widespread, coordinated planting of native milkweed, the only plant their caterpillars eat, and the nectar-rich flowers adults need for fuel. You can see it on the ground in communities from Santa Cruz to Pacific Grove, where local groups have been building out these essential habitats, one garden at a time.
But the pressure is still on. Climate change is a huge, chaotic threat that messes with the delicate timing of monarch migration and breeding. A bigger threat, right now, are the mega-wildfires that can wipe out huge swaths of their habitat in a single season, just like we saw in California during the early 2020s. We’re still trying to figure out how bad the damage was. It’s clear that all our conservation plans have to be climate-proofed now, which means protecting more diverse overwintering sites and pushing for drought-tolerant native plants.
What’s Next for Monarch Conservation
To keep this momentum, we have to figure out exactly *why* the numbers are up. Is it just a few years of lucky weather in the breeding grounds, or have all the habitat restoration projects finally hit a tipping point? It’s probably a mix of both, but researchers need to isolate the most effective actions so we know where to put our money and effort next. Was it a specific regional planting effort? A ban on a certain pesticide? We need to know.
This is also where public buy-in becomes so important. When thousands of people decide to plant native milkweed in their backyards or avoid using systemic pesticides, they are literally building the infrastructure the butterflies need to survive. It’s not just a feel-good activity. At the same time, policymakers need to get serious about protecting the coastal overwintering groves from development and reining in pesticide use in the big agricultural valleys that monarchs have to cross. The fact that the population has rebounded at all shows these efforts can work, but it also shows how vulnerable these butterflies are. They need our constant attention.
The Western monarch’s recent comeback is proof of what can happen when people focus on a goal, but we aren’t out of the woods. The future of these butterflies depends on expanding their habitat, getting real about climate change, and getting more communities involved in creating safe passage for them on the ground.
What is the primary reason for the Western monarch butterfly population decline?
The decline is driven by a few key factors: loss of habitat (especially milkweed for caterpillars and the groves they overwinter in), widespread pesticide use, and the disruptive effects of a changing climate.
Where do Western monarch butterflies overwinter?
They spend the winter in specific groves right along the California coast, clustering by the thousands in eucalyptus, Monterey cypress, and Monterey pine trees that provide the perfect mix of cool, damp air.
How can I help Western monarch butterflies?
You can make a real difference. Start by planting native milkweed and other nectar-rich flowers. Stop using pesticides in your yard. You can also support conservation organizations directly or even join a citizen science program to help count them.
Is the Eastern monarch butterfly population also recovering?
The Eastern monarchs, which migrate all the way to Mexico, face many of the same threats. Their population numbers also fluctuate wildly, and while data for 2026 is still coming in, they’re the focus of their own massive conservation efforts.
What is the Western Monarch Thanksgiving Count?
It’s a huge citizen science project coordinated by the Xerces Society. Every year around the Thanksgiving holiday, volunteers spread out across California to count monarchs in their overwintering spots, giving us the essential data needed to track the entire population.
