Some Aspects in the Ecology of Muscovy Ducks in Mexico

Food habits, nest box management, age-specific growth rates of ducklings and internal parasites of muscovy ducks (Cairina moshata) were studied in Mexico during 1980 and 1981.

Crop contents of adult muscovies from two locations indicated that their diets varied by habitat type. In the marshes of Veracruz, the birds consumed 66% native plant foods and 337o animal matter whereas those samples from an agricultural area in Tamaulipas contained 100% waste corn. These data suggest that muscovies (a) do not occupy specialized food niches, (b) may not cause crop depredations and (c) are infected by internal parasites in proportion to the amounts of animal matter consumed (see below).

Muscovies nested successfully in 2 of the 18 nest boxes (11%) available during one nesting season (1981) and contributed eggs jointly with black-bellied whistling ducks (Dendrocygna autumnalis) in another 2 nest boxes. Other cavity-nesting birds also utilized the nest boxes . In sum, the nest boxes were 100% utilized; 13 of 18 boxes contained nests and 5 boxes were used twice in the same season. With appropriate care (e.g., protection from predators and human disturbances), nest boxes may offer management opportunities for muscovies where riparian forests have been destroyed.

Based on the development of known-age ducklings from semi-domestic hens, muscovies are slow to mature in comparison with several species of other common waterfowl (Anas spp. and Aythya spp.). Plumage development and other data were adopted for application to a system of aging ducklings under field conditions.

Six nematodes, 2 cestodes , 4 trematodes and 1 acanthocephalan were recovered from muscovy viscera. Of the 13 species of helminth parasites, 8 represented new host records. Based only on gross examinations, the parasites had not impaired the physical welfare of their Muscovy hosts. Parasite loads were proportional to diet; muscovies feeding more heavily on animal matter contained more helminths than those feeding on waste corn.