Monarch

Monarch butterflies are pollinators that are well known for their impressive long-distance migration and their recent declines. The species highlights the need for conservation efforts for all pollinators across the nation. Learn more about monarch conservation efforts, including what the U.S. Fish and Wildlife Service is doing and how you can help.

With its iconic orange and black markings, the monarch butterfly is one of the most recognizable butterfly species in North America. Their bright coloration serves as a warning to predators that eating them can be toxic, and monarchs obtain these toxins (called cardenolides) by consuming milkweed plants.

Originally native to North America, the monarch butterfly has dispersed to other parts of the world and non-migratory populations are found from islands in the Pacific Ocean to the western edge of Europe. Despite this expansion, most monarchs continue to live and migrate in North America. North American migratory monarchs are divided into eastern and western populations. The Rocky Mountains generally divide these two populations, limiting their contact. However, the two populations are not completely isolated from each other and still occasionally interbreed. There are also non-migratory monarchs that remain year-round at the southern end of their breeding range in North America, including in parts of Florida, the Gulf Coast and California.

The eastern North American migratory monarch population is the largest population of monarchs, in both individuals and range. The eastern population encompasses upwards of 70% of the total North American monarch range. In the fall, they may fly more than 2,000 miles (3,000 km) to reach overwintering sites in Mexico.

The western North American migratory monarch population is generally found west of the Rocky Mountains. These butterflies can migrate annually 300 to 1,000 miles (about 500 to 1,600 km). The western population overwinters in hundreds of groves (clusters of trees) along the California coast and into northern Baja California, Mexico.