Table 1. Results of the nonparametric Mann-Whitney U-tests comparing pre- and post-harvest distributions of the percentage of nesting habitat left undisturbed by timber harvesting within a 1-km radius of indicated breeding pair (IBP) locations. Tests include all IBP located within 2 km of clear-cut areas. Median percentages of undisturbed nesting habitat and pre/post median differences are presented: a negative difference indicates a lower undisturbed nesting habitat (higher % of clear-cut) after treatment than before, and vice-versa. Statistics are given for all individual species totaling over 30 IBP, for guilds of ground nesters and cavity nesters, and for all species combined. Period IBP numbers Median % of undisturbed nesting habitat Pre/post difference (%) Z† P Ground nesters Canada Goose Pre- 37 97.3 -13.0 -2.224 0.026 Post- 94 84.3 American Black Duck Pre- 241 89.0 -0.4 -0.962 0.336 Post- 344 88.6 Mallard Pre- 12 92.4 1.0 0.817 0.414 Post- 39 93.4 Green-winged Teal Pre- 42 92.9 -10.4 -2.254 0.024 Post- 65 82.5 Ring-necked Duck Pre- 149 93.1 -2.3 -1.092 0.275 Post- 154 90.7 Common Loon Pre- 56 91.8 2.1 0.809 0.419 Post- 71 93.9 Total Pre- 563 91.7 -2.0 -2.152 0.031 Post- 778 89.6 Cavity nesters Common Goldeneye Pre- 144 85.9 -4.2 -0.907 0.365 Post- 162 81.8 Common Merganser Pre- 148 89.9 1.0 -0.428 0.669 Post- 152 90.9 Hooded Merganser Pre- 24 98.7 -0.6 0.053 0.958 Post- 50 98.2 Total Pre- 337 89.6 0.3 -0.165 0.869 Post- 380 89.9 All species total Pre- 901 91.3 -1.6 -1.618 0.106 Post- 1,160 89.7 †: Z approximation of Mann-Whitney U test statistic.