By Paul Dye

It is unknown whether domestication occurred during the pre-Inca period in Peru, or by early Brazilians. In the 1400's Columbus reported seeing natives keeping ducks as large as geese when he visited the West Indies. Brazilian indian villages were reported to be keeping wild-caught muscovy ducks in the 1500's by the Spanish conquistadors. In the 16th century Spaniards and Portuguese took some of the ducks to Europe. They were popular table birds, both in England and America until largely replaced by the Pekin Duck. The above information was condensed from Frank Todd's wonderful book Natural History of the Waterfowl.

The domestic Muscovy, so familiar to most waterfowl fanciers bears only a slight resemblance to its wild ancestor. It is sometimes heavier and coarser in appearance, after being bred for meat for many generations. As with many domestic fowl, it was also selectively bred for lighter colors, possibly to give it a more appealing appearance on market displays when plucked. Many color variations are common in the domestic form, ranging from pure white through grays and browns, to the black and white original color. The domestic form, probably as a result of being selectively bred for lighter coloration, has prominent red facial wartlike areas with large caruncles.

by Paul Dye

If ease of managing, breeding and rearing was the only criteria, muscovies would be one of the least expensive ducks. Alas, this is not the case, but for other reasons. The amount of feed they consume, and the high maintenance required as a result of the squirty messes they leave behind, contribute to the fact that, though not cheap, they remain moderately priced. Also, they seem to have an intolerance to certain pathogens and algae, resulting in sudden die-offs even in free-flying feral domestic flocks. This requires a diligent effort to keep their facilities clean. In colder climates, where below freezing temperatures can occur for days on end, attention has to be paid to keeping them out of the coldest winds, as frostbite of the feet, particularly the webbing, can be a serious problem.

Both males and females reach sexual maturity at 1 year of age, even though they have not yet necessarily attained their full body mass. At any age there seems to be a slight variation in the size and weight of even same sex siblings from the same brood. I get lots of question about the typical size of my muscovies.  My captive birds are usually at or slightly above the top end of the range of weights Sara indicates in her writeup for wild Brazilian birds. You can expect a first year male to grow to approximately 9 lbs and a female to approximately 4.5 lbs.  A fellow aviculturist has advised that on a visit to a Brazilian Zoo he saw muscovies smaller than the ones I keep. I don't doubt that for a minute, as most captive species change slightly over many generations without an influx of new wild blood, unless a concerted effort is made to keep it from occurring. I feel that a slight enlarging over generations is a natural result of the captive-flock environment, where the largest polygamous males are able to dominate the smaller and pass their genes on to a majority of the offspring. Perhaps it's time for a breeder with the facilities and inclination to do so to "breed down" in size, by selecting males from the smallest in each brood.

Their size results in full-winged females being able to fly up onto fence posts and the tops of nest boxes a week or more before the males attain this same ability. At my farm I've learned to wing clip or pinion them before they become proficient flyers, as a visit to one of the trout ponds has, on occasion, resulted in them becoming a meal for a visiting river otter.

When raised with a liberal application of attention and kindness, whole broods of wild-type muscovies become quite tame and trusting. We've often had them be the first of our many species to meet us at the gate, sometimes getting underfoot and making walking difficult. Their feed needs are very basic; they seem to thrive on any good quality pelleted ration, especially if it is supplemented by a little whole grain, such as wheat. They seen to relish an occasional feeding of greens, such as lettuce and will readily take a special treat of dog meal or sea duck feed thrown on the water. Treats are a good way to keep them tame, so you can easily check their condition.

I've found muscovies to be willing and fertile breeders, regardless of whether kept as single pairs or in a flock situation. The biggest problem with the flock-breeding approach is it's impossible to control inbreeding due to their polygamous nature. In a group setting I've observed that one or two of the males seem to be servicing all of the females, while the remaining males "hang out" in bachelor groups. Of course, with such limited bloodlines available in North America, inbreeding, at least with cousins, has been inevitable. Unlike other species I haven't observed any obvious weakening, neurological problems or characteristic changes as a result.

Ground nest boxes in use

Nesting is greatly facilitated by the use of a variety of nest boxes. A wide variety have been successfully used at my farm, from large wood duck-like boxes with 6" to 8" diameter entrance holes to igloo shaped half barrels, to l' by 2' ground nest boxes with either side or end entry holes, to naturally occuring hollow trees and stumps. The muscovy hens are usually wonderful incubators, but frequently, at least in temperate climates, very poor broody mothers. It's purely a guess, but I suspect it's a result of their natural adaptation to a tropical climate where this skill is less critical.

I owe a debt of thanks to several people when it comes to my many years of success in breeding muscovies. Primary among them is my good friend Frank Todd, who many years ago sent me my first muscovies from Sea World in San Diego. These birds were decended from Wildfowl Trust birds that Mike Lubbock had imported from England. For many years, when wild-type muscovies weren't as much in demand as they are today, I was able to afford to keep breeding them by supplying them to a local pastor for the Vietnamese community. It seems they were in great demand for eating. Then a few years ago Dr. Ed Hoffmann from Canada put me in touch with a Mr Dorwart in Nebraska, who although of advanced age, was also breeding muscovies for many years that had come originally from a central american source. Since his flock had grown very small, with no recent offspring, we arranged to swap one of my young hens for an older one of his. This resulted in successful reproduction at both facilities, and gave my bloodlines a new lease on life. More recently I've supplied muscovies to my coauthor of this article, who has been studying muscovies in the wilds of Brazil. Her appreciation of the quality of the birds I supplied has inspired me to continue seeking new bloodlines. Possibly there are some birds unrelated to mine in Trinidad, and also in a small zoo in Brazil. I suspect the difficulty of importing from these countries would make it impossible to obtain these bloodlines, unless it was done through a third country, like Holland or Germany. I hope we find a way....

Some suggested reading to better understand wild muscovies provided by the University of Southern Mississippi is located on the internet at: http://www.gsmfc.org/nis/nis/Cairina_moschata.html

MUSCOVY DUCKS IN THE WILD

by Sarah Stai 

Geographic Range, Habitat, and Diet

Wild Muscovy ducks range from coastal Mexico, through Central America to South America, reaching Peru on the west and Uruguay and northern Argentina in the southeast.  They inhabit wetlands near forested areas, utilizing trees for roosting and nesting.  Muscovies are opportunistic generalist feeders, apparently adapting readily to local conditions. They reportedly consume the roots, seeds, stems and leaves of a variety of aquatic plants, as well as terrestrial vegetation, including agricultural crops.  They have also been reported to eat small vertebrates and invertebrates, such as fish, reptiles, crustaceans, insects, millipedes, and termites.  Muscovy ducks are usually seen alone or in small groups and rarely form large flocks.  They do not have any established migration patterns but may move in response to seasonal water availability.  

Physical Characteristics

Wild Muscovies are overall black in coloration with iridescent dorsal plumage and white wing patches, which may not develop until after the first year of life.  Occasionally wild individuals will have a few white feathers “out of place” (e.g., on neck or breast).  These feathers have been suggested to be a sign of “contamination” of wild Muscovies by domestic stock, but  they more likely represent natural variation in plumage.  Males are almost twice as large (3.0-4.0 kg) as females (1.5-2.0 kg) and have considerably more caruncles (i.e., fleshy outgrowths) around the face and bill.  The typical caruncle pattern for wild males is a black mask of bare skin, which may have ridges or bumps, outlined by red “warts” that vary in number, size, shape, and distribution.  There is also a knobby protrusion of varying size and color over the base of the bill.  Females typically have a black and/or red mask that is flatter than males and covers less facial area; they may also have small red warts within the mask.  

Sarah with "Patches" in Brazil  

Related Waterfowl

Historically, Muscovies have been classified in a disparate tribe of waterfowl known as the perching ducks.  Recent molecular research, however, suggests that Muscovies are not actually close relatives of many other species traditionally placed in this tribe (e.g., Comb duck, Sarkidiornis melanotos, and White-winged wood duck, Asacornis scutalata).  This research, in addition to earlier studies of morphological characteristics, indicates that the Muscovy’s closest relative is the North American Wood duck (Aix sponsa).  

Current Research

Muscovies have been little studied in the wild, which is surprising given their long association with people through domestication and hunting.  Ducks Unlimited de México, A.C. (DUMAC) is managing wild Muscovy populations in Mexico through a nest box program, and studies there have documented some aspects of nesting biology.  Observations are also being made of a small population in southern Texas, at the extreme northern edge of the species’ range, by the Center for Study of Tropical Birds, Inc.  My study, taking place in the Pantanal wetlands of west central Brazil, is the first to focus on mating behavior in the wild.  

About Me and the Pantanal

I am a Ph.D. student in the Department of Biology at the University of Miami.  I have been studying the Muscovy duck since 1997, starting with feral domestic Muscovies in south Florida parks, then venturing to Mexico and Brazil to look for study sites.  I settled on a site in Brazil in 1998 and returned in 1999 for an initial field season.  My season in 2000 marked the first collection of breeding data for my project, and I am planning another field season for 2001.  My site is a cattle ranch about 2 hours south of Cuiabá, Mato Grosso.   The Pantanal, a seasonally inundated floodplain, is a spectacular place to visit and to work.  It is a little-known region outside of Brazil, even though it is the largest freshwater wetland in the world.  Approximately the size of Nebraska, the Pantanal is home to many species of plants and animals found throughout South America, due to its location at the convergence of the continent’s major biomes.   The open landscape makes for good wildlife viewing, and the area is becoming popular with ecotourists.

Behavior of Wild Muscovies

Muscovies can be observed in the wild with a good spotting scope, some knowledge of favored areas, and a lot of patience!  They are quite wary birds and spend a considerable amount of time in the trees, often making them difficult to find, approach, and observe.  They are strong, heavy fliers, and when startled, usually fly until out of sight.  They tend to feed during morning and evening hours and loaf under or in trees during mid-day.  They seem to prefer shallow areas of flooded vegetation (about 6-18” of water) for feeding.  During the breeding season they can most often be found alone or in small groups (up to 5 individuals).  Slightly larger groups (up to 16 individuals) are seen in the non-breeding season.  Muscovies have a unique repertoire of displays used in various contexts – aggression, courtship, vigilance, etc.  These displays, similar in form and function to those observed in the domestic variety, include head bobbing, tail wagging, crest raising, bill clapping, and “hissing.”  Aside from display hisses, and soft quacks and churrs by females, Muscovies do not exhibit vocalizations.

Female at nest in Brazil

My Project in the Wild

I am studying the mating system of wild Muscovy ducks because it is allegedly promiscuity, as opposed to monogamy, which is the predominant mating system in waterfowl.  My observations to date support the assertions of promiscuity, defined as the absence of a male-female pair bond and the occurrence of multiple mating.  The objective of my project is to characterize the mating system and determine whether it meets the criteria of promiscuity.  I conduct observations of social behavior in order to describe male-female relationships and determine whether a pair bond of any kind is formed, and I use DNA to analyze the parentage of offspring in clutches of eggs as an indirect measure of the degree of multiple mating.  Ultimately, I hope to learn what factors have led this system to be an exception to the “rule” of monogamy in waterfowl.  My methods in the field involve behavioral observations, nest monitoring, trapping for banding and blood samples, and censuses.  A particular advantage of studying Muscovies is that they can be identified by natural markings, so it is not necessary to color-band a large segment of the population before learning the movement patterns and social relationships of individuals.  I draw facial profiles of each Muscovy encountered and can distinguish individuals using variation in caruncle and bill patterns as well as unique plumage features.  

My Project in Captivity

In addition to my field work, I am studying wild-type Muscovies in captivity.  I obtained these birds from Paul Dye in 1999.  This part of the study takes place at the Smithsonian Conservation and Research Center in Front Royal, Virginia. In captivity I am conducting mating experiments to examine sperm competition, which occurs in many animals whenever sperm from more than one male are in the female reproductive tract at the same time.  In birds a phenomenon called last-male sperm precedence occurs, meaning that sperm from the last male to mate with a female fertilize a disproportionate number of eggs.  My experiments seek to elucidate the mechanism responsible for this phenomenon, at the same time assessing the relevance of sperm competition to the Muscovy duck mating system.  Assuming that individuals mate multiply, sperm competition has likely played an important role in shaping mating behavior.