Charles W. Shaiffer Kenneth J. Reinecke 1988 <p>We tested predictions from the condition bias hypothesis (Weatherland and Greenwood 1981) regarding the effects of sampling methods of body weights of mallards (<i>Anas platyrhynchos</i>) at White River National Wildlife Refuge (WRNWR), Arkansas, during 24 November-8 December 1985. Body weights of 84 mallards caught with unbaited rocket nets in a natural wetland were used as experimental controls and compared to the body weights of 70 mallards captured with baited rocket nets, 86 mallards captured with baited swim-in traps, and 130 mallards killed by hunters. We found no differences (P &gt; 0.27) in body weight among sampling methods, but body condition (wt/wing length) of the birds killed by hunters was less (P &lt; 0.02) than that of the controls. Power of the test statistics to reject the null hypothesis of equal body weights among sampling methods was &gt; 0.75 for differences &gt; 50 g. The condition bias hypothesis probably applies to ducks killed by hunters but not to trapping operations when substantial (&gt; 20 at 1 time) numbers of birds are captured.</p> application/pdf 10.2307/3801226 en Wiley A field test for differences in condition among trapped and shot mallards article