The eastern monarch population, which winters in Mexico, has declined by over 80 percent in the past 20 years. The overwintering monarch population estimate in 2013-14 (at time of proposed listing) was 0.67 hectares and the 2016-17 winter survey estimate was 2.91 hectares. Reproduction occurs each year in several generations, with the last generation of summer migrating back to Mexico. Although monarchs are found in 49 of 50 states (except Alaska), the core breeding range of the eastern population includes several states in the upper Midwest and Northeast United States. Loss of milkweed (required by monarchs for egg laying and to feed their larvae), loss of nectar sources, insecticide impacts in the U.S., and degradation of overwintering habitat in Mexico are believed to be the threats that have caused population declines. The goal of this habitat restoration and enhancement strategy is to support an average overwintering monarch population occupying 6 hectares in Mexico, as recommended by the Pollinator Health Task Force and the Monarch Conservation Science Partnership.

Coordinated conservation efforts across state lines and including both public and private lands will be necessary to conserve this iconic species. Many individuals and communities have already initiated monarch conservation projects across the country. The Monarch Joint Venture, formed in 2009, has brought together partners from across the United States in a unified effort to conserve the monarch migration. The agricultural community has been actively involved at both the state and national level because of the potential impacts and contributions that this community of land managers can provide. The USDA Natural Resources and Conservation Service (NRCS) is working with agricultural producers in the Midwest and southern Great Plains to combat the decline of monarch butterflies by planting milkweed and other nectar-rich plants on private lands (contact your local NRCS service center to see if your area is participating). This multistate conservation effort builds upon other such efforts in the Northeast (Conservation Plan for New England Cottontail) and West (Lesser Prairie Chicken Range-wide Conservation Plan) to achieve landscape level conservation planning.