|03-16-2009, 07:49 PM||#1|
Join Date: Feb 2008
Location: Santa Clara, California, USA - - R.I.P. - 1954-2012
Mottled Duck Vs. Mallard (Is the Answer Obvious?)
Mottled Duck Vs. Mallard
By Diane Roth Eggeman, Waterfowl Biologist, Florida Fish and Wildlife Conservation Commission (FWC)
The Florida mottled duck is one of approximately 25 closely related, mallard-type species worldwide and is one of only a few nonmigratory ducks in North America. Hunters favor this bird because of its large size and palatability. The conservative, one-bird daily bag limit reflects biologists’ concern for this species’ population status. Mottled ducks in Florida probably never were extremely abundant. Rapid changes in Florida’s landscape during the past 50 years, mostly resulting from agricultural and urban development, raise concerns about the status of mottled duck habitats. However, probably the biggest immediate threat to the conservation of Florida’s mottled duck is hybridization with introduced mallards. The Florida Fish and Wildlife Conservation Commission is attacking this problem on several fronts. There are ways that every concerned citizen, duck hunter or not, can help.
The conservation of Florida’s mottled duck is important for a number of reasons. The range of Florida’s mottled duck is restricted to peninsular Florida. Information from several decades of banding studies combined with recent information from a radio-telemetry study indicate no movement of birds out of this range. Furthermore, Florida mottled ducks are genetically distinct from mottled ducks that occur in Louisiana and Texas. This is confirmed by genetic studies of birds in the three states. Therefore, Florida’s mottled duck is unique and occurs nowhere else in the world. Additionally, the breeding population of Florida’s mottled ducks is relatively small, our best estimate being 30 to 40 thousand birds. The mottled duck is a defining member of the unique suite of species characteristic of the prairie wetlands of southern Florida. These birds are highly valued by wildlife observers and are one of only four species of waterfowl that regularly breed in the state.
Mallards, a species that is closely related to mottled ducks, occur naturally in Florida only as a winter resident. They migrate north to breed in the spring, and thus are reproductively isolated from mottled ducks. However, captive-reared mallards are being released by humans in large numbers in Florida, and these feral birds remain in Florida year-round. These resident mallards are not part of Florida’s native wildlife, and, like most exotic species, are causing problems. Released mallards inter-mix with mottled ducks, and the two species interbreed. FWC biologists frequently observe mixed flocks and pairs and the resulting hybrid offspring. The hybrid offspring are fertile.
Every mallard released in Florida can potentially contribute to the hybridization problem. Because of the relatively small size of the Florida mottled duck population, complete hybridization of the population is a serious concern. Of a sample of 228 mottled ducks collected near Lake Okeechobee, an estimated 5% showed hybrid characteristics.
Mallard releases in other parts of the world have devastated local populations of closely related species. The New Zealand grey duck is an example. Mallards did not occur in New Zealand naturally, but were released to provide hunting stock. Now, approximately 95% of the population of gray ducks are hybrids. The Hawaiian duck is another example. This endangered bird is probably 100% hybridized on the island of Oahu, and likely only exists, genetically intact, on the island of Kauai. Meller’s duck in Madagascar is also highly endangered, and the remaining birds are being hybridized by introduced mallards. The situation in Florida is comparable to these examples in that we have a small, isolated population of a close relative of the mallard. If we can reduce mallard releases in Florida, attrition will gradually reduce the feral mallard population, and hybridizations and the abundance of mallard genes in the mottled duck population also should decrease.
What is Being Done About It?
In its March 2001 meeting, the Florida Fish and Wildlife Conservation Commission (FWC) prohibited the release of mallards on licensed hunting preserves, effective July 1, 2001. An exception is that commercial operations involved in this activity within the past three years (four preserves) would be allowed to continue mallard releases until 2008. Despite these prohibitions, mallard releases will continue, likely by well-intentioned individuals releasing small numbers of ducks on private ponds or community lakes for aesthetic purposes. The best way to reduce these releases is through a public information/education campaign. FWC is distributing a new brochure about this problem and is planning other educational efforts to spread the word. Permitting requirements for directly controlling feral mallard populations may also be relaxed. Biologists are working to develop a genetic method to monitor the extent of hybridization. Once equipped with a reliable genetic technique, wildlife biologists hope to periodically sample the mottled duck population in Florida to better assess the proportion and distribution of hybrids. If funding is available, FWC biologists will initiate a study of the sale and trade of captive-reared mallards in Florida in order to develop an effective, efficient strategy for reducing the problem.
How Can You Help?
The obvious way to help is to not release mallards and not support existing feral mallards by feeding or sheltering them. Most importantly, spread the word to your friends and neighbors that releasing and supporting feral mallards threatens Florida’s mottled duck population. If your golf course or neighborhood association’s lake or pond has mallards, notify the managers of the problem and your concerns and ask for their commitment to not release any more mallards in the future. Most people do not realize the problems or the fact that releasing mallards is illegal. You can contact one of FWC’s waterfowl offices (850-488-5878, 321-726-2862) for more information or for brochures.
All mallards, wild and feral, are protected by federal law and cannot be touched without the proper permits. If ponds or canals near you have mallards during the summer, these are feral introduced mallards. These birds can be removed by Department of Agriculture--Wildlife Services officials who have the proper permits (call 352-377-5556).