Each year from October through February, tens of thousands of monarch butterflies cluster in a grove of eucalyptus and pine trees off Lighthouse Avenue. The Monarch Grove Sanctuary is a small free park where, on cool mornings, you can see the butterflies hanging in dense masses from branches, mimicking dead leaves until the day warms and they open their wings and take flight.
The sanctuary is at its most impressive on bright afternoons when the temperature rises: the trees seem to shimmer as butterflies launch and glide through slanting light. A docent station operates on weekends during peak season, with volunteers on hand to explain the monarch life cycle and the long migration from as far north as Canada. Numbers vary from year to year — in good years the count tops 20,000 — but even a modest showing is a memorable sight. Entry is free.