Northern Prairie Wildlife Research Center
Breeding Range. (Fig. 20). Common on the Missouri Coteau; fairly common on the Northeastern, Southern, and Northwestern Drift Plains; uncommon on the Coteau Slope; uncommon and local elsewhere in the state.
Breeding Habitat. Wetland complexes that contain a variety of wetlands including temporary, seasonal, and semipermanent ponds and lakes; also occurs on shallow river impoundments that are managed for waterfowl use. Occasionally, dugouts and stock ponds are utilized. Gadwalls are generally tolerant of a wide range of salinity and occur regularly on surface water that ranges from fresh to subsaline.
Nesting. Breeding season: Late April to late September; peak, late May to late August. Courtship behavior was observed by Jerome R. Serie in Stutsman County as early as April 21 [1972]. Extreme egg dates (179 nests): May 18 [year?] in North Dakota (Bent 1923) to August 10 [1964] in Stutsman County (RES). Of the total nests with eggs that were recorded, 8 percent were found in late May, 75 percent in June, 17 percent in July, and + percent (one nest) in August. Extreme dates of dependent young (955 broods): June 14 [1917] in Kidder County (H. C. Oberholser) to September 24 [1965] in Stutsman County (RES). Of all broods recorded, 1 percent was observed in June, 45 percent in July, 50 percent in August, and 4 percent in September.
Gadwall nests were found in a considerable variety of habitats. The great majority were found in native prairie (including thickets of low shrubs), retired cropland, hayfields, weedy field borders, and other similar situations. During a study of waterfowl nests along a highway right-of-way in Stutsman County, Getting and Cassel (1971) found significantly higher densities of active Gadwall nests in unmowed sectors than in sectors that had been mowed. Investigations on the Lostwood National Wildlife Refuge by Salyer (1962) indicated that the density of active Gadwall nests during a "good" wet year (1960) was much greater than during a "poor" dry year (1961).
Nesting Gadwalls occasionally concentrate in large numbers on islands that are located on managed river impoundments. In 1947, 106 active nests were found on a l/2-acre island within the J. Clark Salyer National Wildlife Refuge by C. J. Henry and M. C. Hammond. Counts of 78 nests in 1956 and 121 nests in 1957 were recorded on single islands of this refuge, including, in 1957, 28 nests that were located on an area with a 75-foot radius (Duebbert 1966b).
Indicated clutch size (677 nests): 5 to 15 eggs; mean, 9.9 eggs. During 1969 in Stutsman County, Page and Cassel (1971) found that the average clutch size in nine nests representing initial attempts was 10.4 eggs, while the average clutch size in nine nests representing renesting attempts was 8.8 eggs.
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| Figure 20. Breeding Range of Gadwall. |
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U.S. Department of the Interior |
U.S. Geological Survey
URL: http://www.npwrc.usgs.gov/resource/birds/bbofnd/species/1350.htm
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