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The Problem – Hybridization

Male and Female Mallard Pair

Historically, wild mallards (Anas platyrhynchos) normally winter in Florida in widely scattered, small flocks and are seldom seen in large concentrations except in some of the northern counties. These wild birds migrate out of our state to northern breeding areas in the spring and are not present in Florida during the mottled duck breeding season.

However, captive-reared mallards are being unlawfully released by humans in large numbers in Florida. It is estimated that more than 12,000 mallards are purchased statewide from feed-and-seed stores and potentially are released each year. These domesticated mallards are being purchased by well-intentioned individuals and are being released on local ponds, lakes and canals for aesthetic reasons.

Currently, these domesticated mallards can be found year-round throughout Florida on water bodies at city and county parks; apartment and condominium complexes; and in other urban and suburban areas. They are not part of Florida's native wildlife and like other exotic species, are causing problems.

State biologists are observing more and more mixed flocks and mixed pairs in the wild and these feral mallards are mating with mottled ducks, producing a hybrid offspring (see details). These hybrid offspring are fertile, which further compounds the problem. Every mallard released in Florida can potentially contribute to the hybridization problem and the result is that fewer and fewer pure-bred Florida mottled ducks are left each year. An estimated 7 to 12 percent of mottled ducks are already exhibiting genetic evidence of hybridization and biologists list this hybridization as the biggest immediate threat to the conservation of Florida's mottled duck.

Because of the relatively small size of the mottled duck breeding population (estimated at 30,000 to 40,000), the complete hybridization could result in the extinction of the Florida mottled duck.

History has proved that the concern over the loss of the Florida mottled duck to hybridization is a real one and should not be taken lightly.

Other Examples Of Mallard Hybridization:

Mallard releases in other parts of the world have devastated local populations of closely related species.

New Zealand grey duck -- Mallards did not occur in New Zealand naturally, but were released to provide hunting stock. Now because of hybridization, approximately 95 percent of the native gray ducks in New Zealand are hybrids.

Hawaiian duck -- This endangered bird is most likely completely hybridized on the island of Oahu, and may be genetically intact only on the island of Kauai.

Meller's duck -- This highly endangered duck occurs in Madagascar and the remaining birds are being hybridized by introduced mallards.

The situation in Florida with mottled ducks and feral mallards is comparable to these examples in that we have a small, isolated population of a subspecies that is closely related to the mallard.