How to make a way station for traveling monarch butterflies
The iconic western monarch butterfly is in peril. By some estimates, the population of this increasingly elusive pollinator has plunged to a mere 1% of its historic levels. Some scientific models have suggested it is in a death spiral from which it cannot recover.
However dire the situation, there are many citizen scientists, conservationists and home gardeners who are not ready to give up the fight to preserve this majestic butterfly.
Among these champions is the Windsor Garden Club, which has launched a challenge to create 100 monarch way stations in gardens throughout their community. Making a way station is something anyone with even a small patch of garden space can do, said Cindy Fenton, who is leading the project. The effort has been slowed by the coronavirus pandemic, but so far 60 people have signed up.
“I’m in a subdivision in the middle of town. There is not enough habitat left anymore to support the population of insects,” Fenton said. “And the monarch is the canary in the coal mine in our area.”
Scientists say climate change is one of the key factors causing the decline of the monarch, along with pesticides, development and loss of the plants they need for survival.
Suzanne Clarke, a Sonoma County Master Gardener and founder of the Sonoma County Butterfly Alliance, has had a way station in her garden for 20 years. In it is milkweed, essential for the butterflies to lay their eggs on and as food for the caterpillars. Milkweed is the only host plant for the monarch. Clarke also has nectar-producing plants for the butterflies. Even with the declining numbers of monarchs, some usually do visit her oasis. But this year she hasn’t seen a single one.
“This year has really been quite desperate,” she said, attributing the butterflies’ disappearance to the smoke and wildfires that have ravaged the west.
“Smoke forces them to go overland a bit more. They bypass us,” she said.
Each year in fall, monarchs migrate from their summer habitat in Canada back to their overwintering grounds along the Pacific Coast, which historically has stretched from Mendocino County south to Baja, California. It takes several generations to make the trip, since a migrating monarch’s two- to eight-week lifespan is not long enough for the entire journey. Each generational cycle travels, eats nectar, mates and lays eggs that hatch into caterpillars that turn into chrysalises and emerge eight to 15 days later as spectacular orange-and-black-winged butterflies.
Monarchs start arriving at their overwintering sites in September and the first half of October, clustering in groves of eucalyptus, cypress and other large evergreen trees along the coast. At one time there were clusters on the Bodega Dunes and at Sea Ranch. But they have all but disappeared locally, Clarke said. She participates in the annual Thanksgiving butterfly count through the nonprofit Xerxes Society and has been closely watching the local monarch presence for years.
Overwintering monarchs can be found in the branches, leaves and occasionally the trunks of trees. They like evergreens that have some opening for light that provides warmth. This overwintering generation lives much longer than their migrating predecessors, between six to eight months, because they aren’t using energy to reproduce and they are in a very cool location, which slows their metabolism. Through winter they will remain in a state of partial hibernation called diapause, moving only to consume nectar, hydrate or sun themselves. In February or March the survivors will begin moving on, flying north as they chase the nectar of spring flowers.
The Xerxes Society’s monarch count last winter recorded 29,000 of the butterflies, up slightly from the year before when the count dropped to its lowest ever at 27,000. The federal government currently is considering whether to list the monarch butterfly under the Endangered Species Act. A decision is expected by December, according to the U.S. Fish and Wildlife Service.
Washington State University researchers have predicted the monarch will be extinct within a few decades if nothing is done to save it.
That may seem daunting, but there are steps home gardeners can take to support the cause by laying out the welcome mat for traveling or overwintering monarchs. The most important of these is to plant milkweed, the only plant on which monarchs will lay their eggs and which the caterpillars will eat. Other butterflies use other host plants, but for the monarch, the milkweed is it and is key to their survival.
Wildlife groups recommend using only milkweed native to your area. In Sonoma County that would include the narrow-leaved or narrow-leaf milkweed (Asclepias fascicularis) and the showy milkweed (Asclepias sepciosa). The former is weedy and spreads easily. Plant it in a discreet spot where you can keep it drier than other plants to prevent it from spreading too much, Fenton said.