Conditionally Unbiased Estimation of Population Size Under Plant-Capture

A target population is increased by the insertion of a known number of planted individuals. The standard equal catchability model used in mark-recapture is assumed to be applicable to the augmented population. This article considers a conditionally unbiased estimator of the unknown size of the target population. Its performance is seen to compare favorably with that of the maximum likelihood estimator and a Petersen-type estimator. Estimators of the standard deviation of the conditionally unbiased estimator are also considered.