Methods of estimating densities of white-tailed deer

Abstract

Methods of estimating densities of white-tailed deer (Odocoileus virginianus) were examined on the Rob and Bessie Welder Wildlife Refuge, San Patricio County, Texas, from June 1969 through May 1971. Twelve transect estimators were tested on data collected during 17 counts along ten miles of linear transects. Estimators selected from the literature included the King, Hayne, Hahn, Webb, Gates I, Gates II, Dasmann and Mossman, White and Kelker. The normal, stake and P(Y) estimators were developed during the study. Densities from the estimators were compared to densities from helicopter counts. The Hayne, stake, White, normal and P(Y) estimators were not significantly biased. The King estimator was negatively biased. The Hahn, Webb, Gates I, Gates II, and Dasmann and Mossman estimators were positively biased. The Kelker estimator could not be statistically tested but appeared to be insignificantly biased. In terms of statistical efficiency, the unbiased estimators were ranked 1, Hayne; 2, P(Y); 3, stake; 4, normal; and 5, White. Helicopter counts were conducted in the winter of 1969-70 and of 1970-71, and summer 1970, and served as a standard of comparison for the transect estimators and fixed-wing aerial counts. Estimates of density varied from 93 deer per section in the summer to 124 deer per section in the winter. A method of estimating the width of the strip censused from the helicopter was developed and used to adjust estimates of deer density from base counts in the winter, 1970-71. ...