Validity of hunter surveys for daily effort and deer sightings in Vermont

Abstract

AbstractWildlife managers of harvested big game species, such as white‐tailed deer (Odocoileus virginianus), often rely on indices of abundance to monitor population trends and to estimate relative abundance among management units within a jurisdictional unit. Reliable estimates of hunters' hunting effort, harvest, and deer sightings can be used for estimates of relative abundance or population size by catch‐per‐unit‐effort models. I used likelihood‐based information‐theoretic evidence to show that random‐mailing surveys of licensed hunters in Vermont, USA, provided reliable knowledge regarding 1) daily hunter effort, and 2) deer sightings as a convenience index of abundance, during identically structured 16‐day antlered‐deer‐only rifle seasons in mid–late November, 2000–2009. As a covariate explaining daily probability of capture in a harvest‐based catch‐effort multinomial‐likelihood removal model, within‐year daily hunter‐effort data outperformed a larger data set pooled across years, suggesting that within‐year data captured information regarding variability of daily hunter effort among years. Two independent indices of relative abundance that were hunter sighting rates of deer and results of the harvest‐based removal models were well‐correlated at the regional level (n = 60, r2 = 0.74, P ≤ 0.001). Vermont's deer management program uses estimates of relative deer abundance from survey data of hunter effort and deer sightings to help prescribe annual antlerless deer harvests at the regional level, and lesser spatial extents, within its jurisdiction. Other states may find such data similarly valid and useful. © 2011 The Wildlife Society.