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Homing and Reproductive Habits of Mallards,
Gadwalls, and Blue-winged Teal

Results

The number of wet basins present in May on both study areas varied from 31 in 1977 during drought to 335 in 1979 (Table 2). A large spring runoff in 1979 filled all natural wetlands and flooded several lowlands on the Koenig study area adjacent to a new man-made canal. Densities of breeding mallard, gadwall, and blue-winged teal pairs were lowest in 1977 and generally increased through 1980. Blue-winged teal pairs increased through 1981 at the Koenig study area but declined after 1979 on the Woodworth study area.

Table 2.   Mallard, gadwall, and blue-winged teal breeding pairs per km2 and the number of wet basins during May on the Koenig and Woodworth study areas, North Dakota, 1976-81.
Study area and species 1976 1977 1978 1979 1980 1981
Koenig study area
    Mallard 1.9 0.6 2.6 3.3 7.6 5.7
    Gadwall 3.4 0.4 3.2 3.9 10.6 10.4
    Blue-winged teal 11.6 1.9 13.4 15.4 18.8 21.9
        Total 16.9 2.9 19.2 22.6 37.0 38.0
        No. of wet basins 136 16 165 165 49 62
Woodworth study area
    Mallard 8.7 3.1 3.5 3.1 6.6 3.3
    Gadwall 9.3 3.5 5.2 4.4 5.4 3.3
    Blue-winged teal 31.7 8.5 23.2 28.4 18.3 11.6
        Total 49.7 15.1 31.9 35.9 30.3 18.2
        No. of wet basins 134 15 153 170 80 78

During the 6 years of study, nasal markers were attached to 408 mallard, 599 gadwall, and 159 blue-winged teal hens (Table 3). All of these hens plus an additional 53 mallards, 324 gadwall, and 599 blue-winged teal also were leg banded. Another group of 414 mallard and 326 gadwall ducklings at nests were marked with web tags.

Table 3.   Number of nasal-marked mallard, gadwall, and blue-winged teal hens captured by various methods on the Koenig study area, North Dakota, 1976-81.
Species and
trap type		 1976 1977 1978 1979 1980 1981 Total
Mallard
   Drivea 0 4 23 28 10 0 65
   Nest 9 4 25 34 34 21 127
   Rocket-net 8 20 8 6 7 11 60
   Decoy 0 0 1 12 50 87 150
   Other 1 0 2 1 1 1 6
Subtotal 18 28 59 81 102 120 408
Gadwall
   Drivea 29 13 79 53 26 20 220
   Nest 17 4 32 37 31 55 176
   Rocket-net 12 18 6 7 25 22 90
   Decoy 0 0 0 3 27 49 79
   Other 8 0 0 4 4 18 34
Subtotal 66 35 117 104 113 164 599
Blue-Winged teal
Subtotal 0 18 63 56 22 0 159
Grand Total 84 81 239 241 237 284 1166
a Ninety-two percent of mallards and gadwalls captured by drive trapping were HY hens.

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