Observer Group Accuracy in Plotting Locations of Northern Bobwhites when using Fall Covey Calls

Morning covey call counts are popular for estimating fall abundance of northern bobwhite (Colinus virginianus). However, veracity of the technique's abundance estimates are questionable with numerous assumptions inherent to the technique. Therefore, we used captive bobwhites to test ability of three groups of observers to plot calling bobwhite locations on an aerial photo. We found no difference (P < 0.05) between observer groups when plotting calling bobwhites from within a grid cell. Accuracy was generally poor (x¯ = 75.0 m, SE = 10.9) regardless of where in the grid cell the calling bird was located. We also compared accuracy in plotting captive birds and recorded calls and found that recorded calls can be used as a substitute for captive bobwhites when testing observer groups. However, there are potential sources of error including time of day and possibility of observer group accuracy changing as number of attempts to plot coveys increases during the day. We advise caution in using the covey call technique and recommend further research. Key words: Colinus virginianus, covey calls, density, Missouri, northern bobwhite, observer, population estimation, recorded calls

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