Virtual Tour: Visiting the Winter Home of Western Monarch Butterflies
“We hope to raise awareness of their plight and share the amazing story of monarch migration with people who don’t have the opportunity to personally visit the overwintering grounds,” says Service public affairs specialist Joanna Gilkeson. Above, monarch butterflies cannot fly when their wings are wet. This butterfly is waiting out the rain before flying again in Santa Cruz, Calif.

Have you ever seen the amazing assembly of monarch butterflies overwintering along California’s central coast? U.S. Fish and Wildlife Service public affairs specialist Joanna Gilkeson, packed up her camera equipment and drove north along California’s coast to see them for the first time.

“I hope to share the amazing story of monarch migration with people who don’t have the opportunity to personally visit the overwintering grounds,” she said. “Monarchs are declining, and maybe those very people will see these photos and want to help monarchs by planting milkweed or becoming a citizen scientist.”

Gilkeson grew up in Minnesota, where individual monarchs spend their summers looking for nectar and milkweed to lay their eggs before migrating to Mexico for the winter. And from an early age, the butterflies were the topic of many dinner table conversations.

Each summer, her father collected monarch eggs and larva from milkweed in the front yard and reared the monarchs to adulthood, before releasing them back to the wild. Thrilled to see the monarchs in their overwintering grounds, Gilkeson feels like this has brought everything full circle. Monarchs have declined over the last 20 years and Gilkeson believes it’s important to “see their beauty” which she has captured in these photographs.

Join her as she followed the migration of the western monarch butterfly to their overwintering sites in and around Pacific Grove, Calif.

U.S. Fish and Wildlife Service biologists Shauna Marquardt and Ryan Drum visited monarch overwintering colonies along coastal Calif. to see how they were faring this year.
Monarch butterfly gripping a cedar branch in Santa Cruz, Calif. Many people know that monarchs overwinter in large clusters in Mexico, but did you know monarchs living west of the Rocky Mountains overwinter at a few dozen sites along the Calif. coast? Monarchs spend the cool winter months clustered in trees to protect themselves from cold or rainy weather, waiting for the milkweed and flowers that come with springtime.
Monarch clusters on Monterey cypress in Santa Cruz. While monarchs are congregated in one place, scientists estimate their population numbers. Can you guess how many monarchs are pictured here? Our biologists estimate 11,000 monarchs are clustered in this tree. This number might sound promising but overall, numbers are declining.
Monarch butterflies on Monterey cypress in Pacific Grove, Calif. Fortunately, monarchs are astoundingly resilient. When clustered, monarchs exhibit their underwings, disguising the butterflies as dead leaves. This provides some protection against predators.
Up close, the clusters are full of color. Monarch butterflies clustered on a Monterey cypress branch at the Monarch Butterfly Santuary in Pacific Grove, Calif. Arriving in October, monarch butterflies cluster together on pine, cypress and eucalyptus trees. Their migration to the town is so unique that Pacific Grove is nicknamed "Butterfly Town, U.S.A."
During rainy days, monarch butterflies rarely move. They must wait for their wings to dry before taking flight. Increasing extreme winter storms and drought conditions have contributed to declining monarch populations. Monarchs are capable of withstanding freezing temperatures and some rain but not for long periods of time. Monarchs can fly when temperatures are higher than 60 degrees Fahrenheit, and 50 degrees Fahrenheit when sunny.
Monarch butterflies form new cluster on a nearby Eucalyptus tree after winds shift and disturb their site at the Monarch Butterfly Sanctuary in Pacific Grove, Calif. If environmental conditions like rain or wind change for the worst, monarch butterflies will fly to a new location where they can be protected by tree-cover.
Monarchs enjoy sun-bathing. During sunny winter days, the butterflies will disperse from their clusters to bask in the sunshine until dusk, once again, brings cooler temperatures.
Monarch butterflies have been migrating to the West Coast and Mexico to overwinter for centuries. Despite their paramount ability to deal with threats, a butterfly’s natural defenses and endurance can only carry it so far. Habitat loss, extreme weather events and other human-induced threats continue to contribute to their decline.
Can you spot the small, white tag on one of these monarchs? According to Southwest Monarch Study, monarch AM288 (photo center) was tagged by a citizen scientist in Providence, Utah. This marks the first time a monarch tagged in Utah was rediscovered in Calif. Spotted on Dec. 4, 2016, this monarch was originally tagged on Sept. 26, 2016, and flew approximately 655 miles to its overwintering site in Ventura, Calif. You can become a citizen scientist and help document the mysterious movements of western monarchs.

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