Comparison of Helicopter and Ground Surveys for North American Elk Cervus elaphus and Mule Deer Odocoileus hemionus Population Composition


Louis C. Bender;Woodrow L. Myers;William R. Gould

Key Words

age structure ; elk ; ground surveys ; helicopter ; mule deer ; population composition ; sex ratios ; surveys


Wildlife Biology

Volume or Term/Year and Month of Publication

9卷3期(2003 / 09 / 01)

Page #

199 - 205

Content Language


English Abstract

Both ground and helicopter surveys are commonly used to collect sex and age composition data for ungulates. Little attention has been paid, however, to whether data collected by each technique are similar. We compared helicopter and ground composition data for both elk Cervus elaphus and mule deer Odocoileus hemionus across a variety of habitats in the state of Washington, USA. We found that ground and helicopter counts differed (P's<0.002) consistently in male age structure estimates for elk, and that the two survey methods differed in estimates of adult sex ratios for mule deer (P=0.023). Counts from helicopters provided larger sample sizes, tended to be more consistent annually in their results, and were corroborated by other demographic studies of the test populations. We conclude that helicopter and ground surveys differ for male age structure and perhaps male: female ratios, but are similar for young: female ratios. Managers should maintain a standardized technique using the same survey vehicle for trend analysis of composition data.

Topic Category 生物農學 > 動物學