Spinning‐wing decoy use and reported duck harvest in Illinois: Implications for adaptive harvest management

Abstract

AbstractUse of battery‐powered spinning‐wing decoys (SWDs) by duck hunters has generated questions as to the effect these decoys may have on duck harvests. I used data from the annual Illinois Waterfowl Hunter Survey for duck hunting seasons 1999 through 2003 to compare mallard (Anas platyrhynchos) and total duck harvest, reported days afield, and duck crippling rates between hunters using and not using SWDs. For the each of the 5 years reported, mean mallard harvest was greater among hunters using SWDs than among hunters not using the decoys and effect size was substantial (1999: F = 355.01, P < 0.001; 2000: F = 567.92, P < 0.001; 2001: F = 333.25, P < 0.001; 2002: F = 321.58, P < 0.001; 2003: F = 299.00, P < 0.001). Mean reported total ducks harvested was greater for decoy users than non‐users, and I found effect sizes to be substantial for all years (1999: F = 301.80, P < 0.001; 2000: F = 607.76, P < 0.001; 2001: F = 369.49, P < 0.001; 2002: F = 321.59, P < 0.001; 2003: F = 335.82, P < 0.001). Decoy users reported hunting more days than non‐users (1999: F = 71.00, P < 0.001; 2000: F = 716.50, P < 0.001; 2001: F = 486.75, P < 0.001; 2002: F = 410.72, P < 0.001; 2003: F = 466.09, P < 0.001). I observed substantial effect size for days hunted by decoy use for each year except for 1999–2000, for which effect size was typical. Hunters using SWDs reported greater crippled ducks than for hunters not using the decoys, with typical effect sizes observed for each year I examined (1999: F = 168.42, P < 0.001; 2000: F = 361.34, P < 0.001; 2001: F = 163.05, P < 0.001; 2002: F = 153.29, P < 0.001; 2003: F = 169.18, P < 0.001). I did not observe significant relationships between years of hunting experience and decoy use (R2 range = 0.051–0.071). My findings support claims that SWDs lead to increased duck harvests. Recent actions by some state wildlife management agencies have resulted in a mixed approach toward regulating use of SWDs, ranging from prohibiting their use to removing all restrictions. This study seeks to provide managers with greater understanding of potential impacts of SWD use on waterfowl harvests. © 2011 The Wildlife Society.