Using Sign Counts to Quantify Animal Abundance

Abstract

I present a statistical framework for sign counts that permits abundance and density estimation for closed populations (e.g., in respect to ingress and egress). The estimation technique requires the capture, marking, and release of animals so the subsequent sign they produce is distinguishable from unmarked individuals. I develop variance estimators using finite sampling theory for the cases of simple random sampling and stratified random sampling of field plots for animal sign in the landscape. The variance formulas are used to determine the effects of sampling effort on the subsequent precision of abundance estimates. I present sample size formulas to determine the joint levels of marking effort and areal sampling required for a prespecified level of sampling precision in sign-marking studies