Enter your Animals Marked (M), Total in Second Capture (C), and Recaptured (R) into this Mark-Recapture Calculator to get your Estimated Population Size (N), Standard Error, Confidence Interval, and Capture Probability using the Lincoln-Petersen method.
Estimated Population Size (N)
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Standard Error
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Confidence Interval (Lower)
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Confidence Interval (Upper)
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Estimated Capture Probability
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The Lincoln-Peterson estimator is a statistical method used to estimate the size of a wildlife population using mark-recapture data. It assumes that the proportion of marked animals in the recapture sample represents the proportion of marked animals in the entire population.
The method assumes: (1) the population is closed (no births, deaths, immigration, or emigration), (2) marks are not lost, (3) all animals have equal probability of capture, and (4) marking does not affect recapture probability.
Accuracy depends on sample size and how well the assumptions are met. Larger recapture samples generally provide more accurate estimates. The confidence intervals help indicate the reliability of the estimate.
If R = 0, the Lincoln-Peterson estimator cannot be calculated as it would involve division by zero. This suggests either a very large population or violations of the method's assumptions.
Yes, but it works best for species that can be safely captured, marked, and released without affecting their behavior or survival. It's commonly used for fish, birds, small mammals, and some insects.
Capture probability indicates how likely an individual animal is to be caught in a sampling effort. Low capture probabilities may indicate the need for different sampling methods or longer sampling periods.
The time between sessions should allow marked animals to mix randomly with the population but be short enough to maintain population closure. This varies by species but is typically days to weeks.