To ensure healthy ecosystems, the Xerces Society’s endangered species team conserves at-risk species and their habitats through research, advocacy, education, conservation planning, and restoration. Our team of conservation biologists holds degrees in entomology, ecology, biology, and environmental science, and has decades of experience working with rare and at-risk terrestrial and aquatic invertebrates. We share a passion for conserving invertebrates that are imperiled with extinction.
Since the 1980s, the Xerces Society has worked to protect monarch butterflies—including the western population of monarchs that overwinters in forested groves along the California coast. We help facilitate the Western Monarch Thanksgiving and New Year’s Counts, community science projects in which volunteers track the size of the monarch population at overwintering sites annually.
Our roads and highways present unique opportunities for creating corridors to support monarchs and other pollinators. In some areas, roadsides may be the only places where milkweed and nectar plants may be available. When managed with pollinators in mind, roadsides have the potential to add miles and miles of high-quality habitat while reducing maintenance costs. Learn more about how roadsides can be managed to reduce costs and protect pollinators.
As habitat is lost or degraded elsewhere, parks, gardens, and greenspaces can all be managed to provide resources for monarchs and other pollinators.
In the 1990s, nearly 700 million monarchs made the epic flight each fall from the northern plains of the U.S. and Canada to sites in the oyamel fir forests north of Mexico City, and more than one million monarchs overwintered in forested groves on the California Coast.
Milkweeds (Asclepias spp.) are the required host plants for caterpillars of the monarch butterfly and thus play a critical role in the monarch’s life cycle. The loss of milkweed plants in the monarch’s spring and summer breeding areas across the United States is believed to be a significant factor contributing to the reduced number of monarchs recorded in overwintering sites in California and Mexico.
Monarchs are in decline across their range in North America. Loss of milkweed host plants due to extensive herbicide use has been identified as a major contributing factor, and loss or degradation of nectar-rich habitat from other causes, natural disease and predation, climate change, and widespread insecticide use are probably also contributing to declines.