The Muscovy duck (Cairina moschata) is a large waterfowl species frequently encountered in urban and suburban environments across the United States. Distinctive for its size and the red, fleshy growths on its face, or caruncles, the duck’s presence outside its native range often leads to confusion regarding its legal standing. This regulatory ambiguity stems from the bird’s historical domestication and its subsequent establishment of free-roaming, or feral, populations in areas where it is not naturally found, raising questions about whether it is protected wildlife, a nuisance species, or an invasive threat.
Native Origin and Global Dispersion
The Muscovy duck is native to the Americas, with its wild range spanning from the lower Rio Grande Valley in Mexico south to Argentina and Uruguay. Within the contiguous United States, the species is indigenous only to Hidalgo, Starr, and Zapata Counties in southern Texas. Outside of this region, the Muscovy ducks encountered today are descendants of domesticated stock introduced globally centuries ago for meat and egg production. These feral populations established themselves after escaping captivity or being intentionally released, proving highly adaptable to various climates.
Feral Status: Are They Truly Invasive?
The status of the Muscovy duck in the United States is defined by a specific federal regulatory distinction that makes them functionally a non-native nuisance species. While the wild population in South Texas is protected under the Migratory Bird Treaty Act (MBTA), the feral populations found elsewhere in the country are explicitly excluded from this protection. The U.S. Fish and Wildlife Service (USFWS) issued a control order designating the non-native, feral Muscovy duck as a species that can be managed without federal permits. This regulatory action essentially treats them as non-native poultry outside their natural range. This control order allows landowners and wildlife management agencies to remove or destroy the ducks, their nests, and their eggs at any time without a federal permit in most states.
Impacts on Native Ecosystems
Feral Muscovy duck populations cause several ecological problems, justifying their designation as non-native pests. Their primary ecological threat is the potential for hybridization with native waterfowl, such as Mallards and Florida Mottled Ducks. Although Muscovy ducks belong to a different genus, they can interbreed, resulting in sterile offspring often referred to as “mule ducks.” This interbreeding risks diluting the gene pools of native species, a form of genetic pollution that compromises genetic integrity. Feral populations also introduce resource competition and water quality degradation. They aggressively compete with native ducks for food and nesting sites, potentially displacing native species from urban water bodies. Their large size and high volume of waste contribute to nutrient loading in small ponds and lakes, which can lead to water quality issues and increase the risk of disease transmission.
Regulations Governing Muscovy Ducks
Although the USFWS control order removes federal protection for feral Muscovy ducks, management remains subject to local and state laws. Landowners and property managers are authorized to remove the ducks, but they must adhere to state and municipal regulations regarding control methods. Federal regulations prohibit the release or relocation of captured Muscovy ducks to a new area, as this simply transfers the problem and is often illegal under state law. Common control strategies focus on population reduction through non-lethal and lethal means. Humane removal methods, such as live-capture netting and trapping, are frequently used, along with the destruction or donation of the removed birds. A non-lethal technique often utilized is egg addling, which involves shaking or oiling eggs to prevent them from hatching while keeping them in the nest. This method prevents the female from simply laying a new clutch, providing a more effective long-term population control measure.