"In my purist world, I would personally be inclined to turn [the grove] into a lovely gully full of willows," Tim Hyland told Bay Nature last year. Hyland is the natural resources program manager for California State Parks in Santa Cruz County. The grove he means is the eucalyptus stand at Natural Bridges State Beach. He has watched crowds gather there every winter, and he came around to a different view. "When you do zoom out, it's a pretty small patch of territory to give up for a pretty big win."
The numbers from last winter suggest the win is bigger than he knew. As the western monarch migration keeps shrinking, a large share of the butterflies left spent last winter in Santa Cruz. The new tracking data shows that those butterflies use far more of the city than the boardwalk on the Westside.
One grove, a fifth of the state
The Xerces Society's Western Monarch Count, released January 29, 2026, counted about 12,260 monarchs across 249 sites during the peak window of late November through early December 2025. That is the third-lowest total since the count began in 1997. The two lower totals both came recently: 1,901 in 2020 and 9,119 in 2024. In the 1980s, western monarchs regularly numbered in the low millions.
"Western monarchs are in serious trouble. The migration is collapsing," Xerces senior conservation biologist Emma Pelton said in the release.
The same release named Natural Bridges as the site with the highest count of the season: 2,500 monarchs in early December. That works out to roughly one in five of every monarch counted in California during the 2025 Thanksgiving window, all in one Santa Cruz grove. The Pacific Grove Monarch Sanctuary, the better-known grove across the bay, recorded 188 at mid-season. Pismo State Beach Monarch Grove recorded 471.
Lighthouse Field State Beach, the city's other well-known grove, went the opposite way.
| Site | 2024 mid-season count | 2025 mid-season count | 2025–26 late-season count |
|---|---|---|---|
| Natural Bridges State Beach | 1,400 | 2,500 | 1,540 |
| Lighthouse Field State Beach | 1,406 | 1,095 | 804 |
| California statewide total | 9,119 | 12,260 | n/a |
In the 2024 mid-season count, which ran November 16 to December 8, the two groves were nearly tied. A year later Natural Bridges had almost doubled while Lighthouse Field fell by about a fifth. By the late-season count, which closed January 11, 2026, both sites had thinned, but Natural Bridges still held nearly twice as many butterflies. Together the two groves held about 3,600 monarchs at mid-season 2025, close to three in ten of the statewide total.
The radio tags offer one explanation for why two groves this close together can move in different directions.
Where the Lighthouse Field monarchs went
In the 2025–26 season, Xerces, Point Blue Conservation Science, Althouse & Meade, California State Parks, Santa Cruz County Parks and other land managers put ultralight radio tags on monarchs at three Santa Cruz groves: Natural Bridges, Lighthouse Field and Moran Lake County Park. KQED reported that the team tagged more than 40 monarchs in the county, out of roughly 100 tagged along the West Coast.
Researchers followed the tagged butterflies through February. The spring 2026 issue of Xerces' Wings magazine described what turned up:
- LF043 and LF006, both tagged at Lighthouse Field, were picked up inland near a lesser-known overwintering site on the UC Santa Cruz campus and in the surrounding neighborhoods.
- ML004, tagged at Moran Lake, flew south more than 100 miles in two days. Xerces' December release named Cambria as where it ended up.
- Several monarchs moved between overwintering sites and across nearby towns.
Xerces drew the conclusion itself: the findings "highlight the importance of smaller, lesser-known sites as part of the overwintering Monarchs' habitat." So a monarch counted at Lighthouse Field in November may spend part of the winter near campus or in nearby residential trees. A count at a single grove captures one moment in a network that crosses the city.
Another tagging season appears to be lined up. On October 12, 2026, the Project Monarch deployment tracker lists a California Department of Fish and Wildlife deployment of 10 tags in Santa Cruz for "Winter 2026," with the status "Tags in hand." That listing does not say the effort continues the Xerces and Point Blue study, and no results exist yet.
The trees doing the work are the ones that burn
Hyland's comment about willows reflects a real conflict. The grove that sheltered the state's largest cluster last winter is non-native eucalyptus, and he told Bay Nature it has burned six times in the past 30 years. State Parks clears debris regularly so that future fires stay manageable.
The most recent fire was not long ago. On June 19, 2025, two vegetation fires broke out at Natural Bridges, one of them a fast-moving fire in the eucalyptus west of the visitor center, according to the Santa Cruz Sentinel. Responders had both contained by 4:30 p.m., the visitor center was not damaged, and the park reopened the next day with the Butterfly Grove walkway open.
Six months later, that grove held the highest monarch count in California. Pelton explained to Bay Nature why the people managing these sites and the people protecting monarchs want the same thing: "If a site totally burns down, that does not benefit monarchs. It doesn't benefit human communities." Xerces biologist Isis Howard made a similar point in the Sentinel's December 2025 coverage. Once winter habitat is destroyed, there may be no suitable replacement, and new trees take decades to grow.
Federal protection is still on paper
As of October 2026, the monarch still has no federal protection. The U.S. Fish and Wildlife Service proposed listing it as threatened on December 12, 2024, and a final rule was first expected around December 2025. The agency later moved the rule to "long-term action." The agency's monarch page, updated September 21, 2026, says the species is not federally listed and no final ruling has been issued.
On September 30, 2026, the parties to a lawsuit over the delay filed a proposed settlement. If a court approves it, a final listing determination would be due by June 6, 2030. The settlement does not decide whether the monarch will be listed, and according to the Monarch Joint Venture's status tracker, it takes effect only once a court approves it. In the meantime, the groves depend on local management by State Parks, the county and partners like those behind the tagging study.
Timing this season's visit
The arrival has started. Natural Bridges hosted Welcome Back Monarchs Day yesterday, October 11, with live music, crafts, pumpkin ice cream and a children's parade. According to California State Parks, monarchs usually arrive in mid-October and leave by mid-February, and "late October and all of November" is often the best time to see them. Last season's numbers fit that window: the grove's peak count came in early December, and the January count was lower.
Temperature matters more than the calendar. State Parks says monarchs cluster in the eucalyptus when it drops below 60°F. Visit Santa Cruz County puts the flight threshold at 55°F, and KQED reported a figure under 56°F, along with an interpreter's advice to come in the afternoon to see the butterflies flying. A cool, gray morning is the best time to see dense clusters hanging in the branches. A warm afternoon is when they fly.
Park hours: 8 a.m. to sunset.
Visitor center: Open daily from 11 a.m. to 4 p.m. between October 1 and January 31, then Friday through Monday from February through September.
Parking: $10 vehicle day-use fee.
Access: State Parks describes the Monarch Grove boardwalk as wheelchair- and stroller-accessible. The self-guided trail is open during park hours from October through January.
Guided walks: State Parks says volunteers lead guided walks, and its Natural Bridges page lists school-group Monarch Tours running October through January.
The season ends with the Migration Festival. The Santa Cruz MAH billed the 2026 festival on February 14 as the 39th annual, free, from 11 a.m. to 4 p.m. State Parks' event list now shows "Feb 13" for the next festival but does not give a year, so check the date as winter goes on.
If you see a monarch away from the groves, perhaps near campus or in a garden, you can log it on iNaturalist. Pelton has said that data helps scientists decide where to focus conservation work. The Project Monarch app shows tagged butterflies moving in near real time, and last season it tracked LF043 and LF006 across the city.
Part of what makes a Santa Cruz home special is having a grove like this a short drive away. If a November walk under the eucalyptus has you thinking about your own place on this coast, Caroll Basile can prepare a calm, detailed free home valuation, with the same care you would want for anything this rare.
