Monarch butterflies cluster together in winter.
MONARCH GROVE SANCTUARY
Like bears, monarch butterflies like to pick a winter refuge. In Pacific Grove, off Highway 1 near Monterey, eucalyptus trees shelter some 19,000 of them yearly from November to February. At the Monarch Grove Sanctuary on Ridge Road, the sun may warm the insects enough to set them aflutter. "It's like looking through a living stained glass window," says Jack Beigle, a grove volunteer. Monarch Madness on November 28 features kids' activities and butterfly gardening tips—and a docent all day.
(831) 648-5716, pgmuseum.org/Monarchs.htm.
The butterfly habitat at Six Flags in Vallejo, Calif., houses 45 to 60 species in a 6,000-square-foot enclosure with a waterfall, two ponds, a cave, and year-round 80-degree temperatures. (707) 643-6722, sixflags.com/discoverykingdom.
TROPICAL BUTTERFLY HOUSE
Escape Northwest rains in the Tropical Butterfly House at Seattle's Pacific Science Center, where some 700 winged insects—golden helicons, scarlet swallowtails, and more—flutter year-round. (206) 443-2001, pacsci.org/butterflies.
Photography from John Hendrickson/Larry Ulrich
This article was first published in November 2009. Some facts may have aged gracelessly. Please call ahead to verify information.