Estimating Population Size in Logistic Capture-Recapture Models with a Known Sex Ratio

ABSTRACT

A logistic model based on capture-recapture data with a known sex ratio is studied. The maximum likelihood estimate for population size is obtained and its large sample properties are derived. Simulation results are reported and an example is given. By using the additional information of the known sex ratio, the accuracy of the proposed method improves considerably.

Keywords:

• Capture-recapture
• Logistic function
• Maximum likelihood estimate
• Sex ratio

Mathematics Subject Classification:

• 62D05
• 62F10

Acknowledgments

This work is supported by the National Natural Science Foundation of China (10471004), RFDP, and the National Basic Research program of China under Grant 2003CB716101. The authors are grateful to the referee for the valuable suggestions.

Notes

p _m  = overall capture probability of males; p _f  = overall capture probability of females; ŝ _{N m}  = average of standard error estimates; P _c  = coverage frequency of the 95% confidence interval, standard errors of simulations in the parenthesis.

P _c  = coverage frequency of the 95% confidence interval; cv = coefficient of variation, standard errors of simulations in the parenthesis.

cv = coefficient of variation, standard errors of simulations in the parenthesis.

Standard errors of simulations in the parenthesis.

Standard error estimates in the parenthesis.