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Photo by Steven L. Hamilton
Photo Copyright Steven L. Hamilton
Mallard
Anas platyrhynchos
NatureServe conservation status
Global (G-rank): G5
State (S-rank): S4S5B,S4N
External links
General information
The mallard, Anas platyrhynchos, is a dabbling duck that breeds throughout much of Canada, the United States, and Mexico. Northern populations migrate south for the winter; most wintering areas are south of southern Canada. The mallard is a common breeder in Utah, and it can be found statewide throughout the year.
Mallards prefer wetlands and fields near wetlands, generally nesting on land close to water in standing crops or other vegetation. In addition, they are well adapted to areas with human disturbance, such as city parks and ponds. Females typically lay five to fourteen eggs; the eggs are incubated by the female alone for about one month. The young are able to fly about two months after hatching.
Mallards are opportunistic feeders that consume grains, aquatic plants, seeds, terrestrial insects, aquatic invertebrates, and small fishes. The female is a drab brown color, which enables her to hide from predators. The male, on the other hand, is more brightly colored, with a green head and a white ring around the neck. Mallards are extremely popular with waterfowl hunters, likely being the most commonly pursued duck species in Utah.
Species range
BREEDS: Alaska, Mackenzie Delta, southern Keewatin, and Maine south to southern California, Mexico, Oklahoma, and Virginia. Has expanded range in eastern North America (especially in the north) in recent decades (see Heusmann 1991 for a detailed account of status in the Atlantic Flyway). WINTERS: southern Alaska and southern Canada to southern U.S., Mexico, Cuba, occasionally Hawaii (AOU 1983). Half or more of the Mississippi Flyway's 3.2 million mallards winter in the lower Mississippi Valley, from Cape Girardeau, Missouri, to the Gulf of Mexico. Also occurs in the Palearctic. Many semiferal populations exist. Availablity of grain allows wintering north of pre-settlement range; now rare in Central America.
Migration
Extent of southward migration may depend on winter temperature, water conditions, and population size. Arrives in northern breeding areas in late March and early April, in far north from mid-May into June. Departs from northern breeding areas late September into November (may depart from far north by mid-August) (Palmer 1976). Makes postbreeding migration to molting area; females that nested in Suisun Marsh, California, began leaving in late May, 50% had departed by mid-June, and nearly all had departed by mid-July; migrated mainly northward to areas in California and south-central Oregon, 12-536 km from nesting sites; exhibited fidelity to molting area (Yarris et al. 1994).
Habitat
Primarily shallow waters such as ponds, lakes, marshes, and flooded fields; in migration and in winter mostly in fresh water and cultivated fields, less commonly in brackish situations (AOU 1983). See Nichols et al. (1983). Adapted to dynamic wetland conditions that provide a variety of wetland types in relatively close proximity (Allen 1986, which see for details on winter habitat in Lower Mississippi Valley). In Maryland, breeding pairs and broods used stormwater-control basins, especially permanent ponds with gently sloping sides (Adams et al. 1985). In California and Oregon, molting areas were dominated by bulrush and cattail and were traditionally flooded in summer and often associated with lakes or rivers (Yarris et al. 1994). Usually nests on ground in concealing vegetation, sometimes in trees or in atypical situations. Nest usually within 0.8 km of water (Palmer 1976). Commonly uses man-made ponds. Successful nesters are more likely to return to the same nesting site in successive years than are unsuccessful nesters.
Food habits
Eats seeds, rootlets, and tubers of aquatic plants, seeds of swamp and river bottom trees, acorns, cultivated grains, insects, mollusks, amphibians, small fishes, fish eggs; adults eat mostly vegetable material, young initially eat mainly invertebrates. Foraging opportunities optimal where water depth less than 40 cm. See Allen (1986) for further details on diet.
Ecology
Breeding density (2.3-9.5 birds per sq km) fluctuates with pond abundance in prairie pothole region (Krapu et al. 1983). In Manitoba, nesting home range size averaged 283 hectares (Dzubin 1955). Average breeding home ranges of radio-tagged birds in Minnesota were 210 hectares (12 females) and 240 hectares (12 males); range 66 hectares to 760 hectares (a pair, Gilmer et al. 1975). In winter, may fly up to 48 to 64 kilometers to forage from roost sites. Does not defend rigid territories, but area immediately surrounding the female usually defended by the male. Broods susceptible to mink predation. Resident birds have higher reproduction whereas migrants have higher survival (Hestbeck et al. 1992). May be negatively impacting black duck populations in eastern North America as a result of competitive interactions (Merendino and Ankney 1994).
Reproductive characteristics
Clutch size is 5-14 (usually 8-10). Incubation, by female, lasts 26-30 days. Young first fly at 49-60 days. First breeds at 1 year. May attain high nesting density (up to at least about 400 nests/ha) on islands free of mammalian predators.
Threats or limiting factors
The recent decline is not simply a reflection of reduced number of wet ponds for breeding (Johnson and Shaffer 1987).
References
- Biotics Database. 2005. Utah Division of Wildlife Resources, NatureServe, and the network of Natural Heritage Programs and Conservation Data Centers.
- Peterson, R. T., and V. M. Peterson. 1990. A field guide to western birds, 3rd ed. Houghton Mifflin, Boston. 432 pp.
