In the Schnabel method of estimating number of animals, the number of recaptures has been assumed to follow a Poisson distribution. This approximation is useful in testing differences in population levels when the Schnabel method is used for estimation, since the distribution of recaptures from one population, conditional on the total number of recaptures from both populations, is approximately binomial with parameters n and p, where p is a function of the parameters of the two Poisson distributions. Tests based on this conditional binomial distribution are described. Confidence limits of the population numbers have been considered and a stop rule developed for the Schnabel experiment used at the second stage of a paired comparison. Mark and recapture is a method commonly used in ecology to estimate an animal population's size. A portion of the population is captured, marked, and released. Later, another portion is captured and the number of marked individuals within the sample is counted. Since the number of marked individuals within the second sample should be proportional to the number of marked individuals in the whole population, an estimate of the total population size can be obtained by dividing the number of marked individuals by the proportion of marked individuals in the second sample. The method is most useful when it is not practical to count all of the individuals in the population. Other names for this method, or closely related methods, include capture-recapture, capture-mark-recapture, mark-recapture, sight-resight, mark-release-recapture, multiple systems estimation, band recovery, the Petersen method, and the Lincoln method. Population size can be estimated from as few as two visits to the study area. Commonly, more than two visits are made, particularly if estimates of survival or movement are desired. Regardless of the total number of visits, the researcher simply records the date

In the Schnabel method of estimating number of animals, the number of recaptures has been assumed to follow a Poisson distribution. This approximation is useful in testing differences in population levels when the Schnabel method is used for estimation, since the distribution of recaptures from one population, conditional on the total number of recaptures from both populations, is approximately binomial with parameters n and p, where p is a function of the parameters of the two Poisson distributions. Tests based on this conditional binomial distribution are described. Confidence limits of the population numbers have been considered and a stop rule developed for the Schnabel experiment used at the second stage of a paired comparison. Mark and recapture is a method commonly used in ecology to estimate an animal population's size. A portion of the population is captured, marked, and released. Later, another portion is captured and the number of marked individuals within the sample is counted. Since the number of marked individuals within the second sample should be proportional to the number of marked individuals in the whole population, an estimate of the total population size can be obtained by dividing the number of marked individuals by the proportion of marked individuals in the second sample. The method is most useful when it is not practical to count all of the individuals in the population. Other names for this method, or closely related methods, include capture-recapture, capture-mark-recapture, mark-recapture, sight-resight, mark-release-recapture, multiple systems estimation, band recovery, the Petersen method, and the Lincoln method. Population size can be estimated from as few as two visits to the study area. Commonly, more than two visits are made, particularly if estimates of survival or movement are desired. Regardless of the total number of visits, the researcher simply records the date