SEDL / STP / STP817-EB / STP30185S

An Evaluation of Visual Counts for Censusing Ground Squirrels

Fagerstone, KA
Research biologist, U.S. Fish and Wildlife Service, Denver Wildlife Research Center, Denver, Colo.

Pages: 8    Published: Jan 1983

Download this paper for $25 PDF (128K)          View License Agreement
Abstract

Visual counts frequently are used to census ground squirrels before and after a control program. However, the precision of visual counts is not known. During 1979 and 1980 I compared visual counts of Richardson's ground squirrels (Spermophilus richardsonü elegans) with mark-recapture population estimates on a study area near Kremmling, Colo. There was no significant correlation between the population estimate generated over a five-day trapping period and the highest visual count on a particular day within that period (R = 0.42, P = 0.06). However, there was a significant correlation between the population estimate and the highest ground squirrel count during the five-day period (R = 0.65, P = 0.009). Therefore, if certain guidelines are followed, visual counts may be reliable indices of ground squirrel populations.