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- Author or Editor: P.P. Woronecki x
Each of 11 cultivars of sweet corn (Zea mays L.) was presented to red-winged blackbirds (Agelaius phoeniceus L.) in an aviary under no-choice conditions in 1985. This evaluation was repeated in 1986 with eight cultivars, five of which had been tested in 1985. In both years, there were significant differences in damage among cultivars; the damage rankings of the cultivars tested in both years were correlated. Total husk weight and husk weight beyond the cob tip individually explained 68% to 69% of the variation in damage among cultivars. Husk characteristics were more important than kernel characteristics in determining the amount of damage a cultivar received. Six of the cultivars evaluated in a field test near a blackbird roost showed differences in damage similar to that found in the aviary. In the field test, the most- and least-resistant cultivars had 16% and 76% of the ears damaged, respectively. Resistance is a viable approach to reduce damage in situations where sweet corn is grown near concentrations of blackbirds.
Twenty-five cultivars of sweet corn were evaluated for resistance to bird damage in an aviary during 1983 and 1984. A free-choice test was used in which red-winged blackbirds (Agelaius phoeniceus L.), common grackles (Quiscalus quiscula L.), and starlings (Sturnus vulgaris L.) could select from among 8 cultivars at a time. In addition, no-choice conditions in which red-wings were presented with only one cultivar at a time were tested. In the free choice test, there were significant differences among bird species and corn cultivars in the amount of damage. The most damaged cultivar had 4.8 times the damage of the least damaged cultivar. Starlings did the most damage and grackles the least, but all bird species damaged the cultivars in the same approximate order. Differences in damage among cultivars were diminished in the no-choice tests; however, the damage ranking of cultivars was similar to that of the free-choice test. Husk weight, length of husk beyond kernels, and weight of husk extension were the best correlates (all negative) with damage. The incorporation of these characteristics into sweet corn lines should increase cultivar resistance to damage by birds.
A study was conducted during 1986 and 1987 to evaluate the nature, extent, and severity of bird depredations on ripening apples (Malus domestica Borkh.) in the mid-Hudson Valley of New York. During the first year of the study, information was solicited through cooperative extension fruit agents, in fruit-grower newsletters, and at fruit-grower meetings. In addition, growers were questioned and bird damage was looked for during the course of other projects in orchards. Whenever damage was found, the owner or manager was interviewed, the planting was inspected, and the overall percentage of crop damaged (<1%, 1% to 10%, >10%) was recorded.