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Survival and Behavior of Hand-Reared Mallards Released in the Wild
John L. Schladweiler and John R. Tester
The Journal of Wildlife Management
Vol. 36, No. 4 (Oct., 1972), pp. 1118-1127
Stable URL: http://www.jstor.org/stable/3799240
Page Count: 10
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One hundred seventy-nine hand-reared mallards (Anas platyrhynchos) of two genetic strains were banded and released in two areas of Minnesota. One area usually had high and the other low natural productivity of waterfowl. Eighty birds were marked with miniature radio transmitters prior to release. Mortality, movements, and habitat use were determined by radio-tracking. Forty of the 56 radio-marked birds that were monitored died within 21 days of release. Mink (Mustela vison) killed 21, avian predators killed 7, and unknown mammalian predation accounted for 9 deaths. Starvation, poaching, and unknown predation were each responsible for one death. Twelve carcasses of banded birds were found. Mink predation was the cause of death in all these cases. In addition, 9 radio-marked and 16 banded birds were shot by hunters. There was no measurable difference in survival between genetic strains or sexes. Ducklings released in the area of high natural productivity had significantly (P < 0.01) lower mortality than birds released in the area of low natural productivity. This lower mortality was attributed to differences in fertility and vegetation on the two areas. No significant difference (P < 0.05) in mortality between radio-marked and control birds was noted. Most mortality occurred within a 2-week period after release. Released birds gathered in large groups. Our findings are in close agreement with previous studies and indicate low survival and a high vulnerability to the gun. Lack of wariness, tendency of birds to gather in large groups, and releases in habitat of poor quality were the main factors contributing to the low survival of the hand-reared mallards.
The Journal of Wildlife Management © 1972 Wiley