J. R. Heffelfinger

Evaluation of Bias in the Proportion of White-tailed Deer Fawns Sighted from Helicopters

We marked fawns and adult white-tailed deer (Odocoileus virginianus) on 2 south Texas areas during 1986-88. Deer sighted on repeated helicopter flights were evaluated to determine if the age ratio of sightings matched the known ratio of marked fawns-to-adults in the populations. There was a trend toward undercounting fawns on each area.

Classifying Male White-tailed Deer from a Helicopter

We evaluated how well observers in a helicopter classed male white-tailed deer (Odocoileus virginianus) into groups ≤3.5 or ≥4.5 years old. Resightings of individually marked anti previously aged deer on 2 southern Texas ranches were used for evaluation during repeated helicopter surveys from 1986 to 1988. Classifications of marked males were at least ≥90% correct on 11 of 14 flights on 1 ranch and 6 of 14 on the other. Although accuracy was acceptable on many flights, some flights gave inaccurate estimates (> 10% misclassified) of male composition. Because managers make only a single,...

Accuracy of Track Counts to Estimate White-tailed Deer Abundance

We assessed the accuracy of population estimates of white-tailed deer (Odocoileus virginianus) determined from track counts by comparing them with aerial mark-recapture estimates on 2 southern Texas areas. Track counts produced very conservative estimates in relation to mark-recapture methods and failed to detect a population increase on 1 area. However, they reflected a large difference in density between the 2 areas.