Description Usage Arguments Details Value Author(s) References See Also

Estimates population size, with variance estimated using Wong's (1996) estimator. This function will usualled be called by Sight.Est function (but see details).

1 |

`total` |
Number of animals in each independently sighted group |

`srates` |
Vector of plot-level sampling probabilities (same dimension as |

`nh` |
Number of sample plots in each stratum |

`Nh` |
Number of population plots in each stratum |

`stratum` |
Stratum identifiers (associated with the independently observed animal groups) |

`subunit` |
Plot ID (associated with the independently observed animal groups) |

`covars` |
Matrix of sightability covariates (associated with the independently observed animal groups) |

`beta` |
Logistic regression parameter estimates (from fitted sightability model) |

`varbeta` |
Estimated variance-covariance matrix for the logistic regression parameter estimates (from fitted sightability model) |

`smat` |
Estimated variance-covariance matrix for the inflation factors (1/probability of detection). This is an n.animal x n.animal matrix, and is usually calculated within the Wong.est function. Non-null values can be passed to the function (e.g., if a bootstrap is used to estimate uncertainty due to the estimated detection parameters). |

This function is called by Sight.Est, but may also be called directly by the user (e.g., in cases where the original sighability [test trial] data are not available, but the parameters and var/cov matrix from the logistic regression model is available in the literature).

`tau.hat` |
Sightability estimate of population size, tau^ |

`Vartot` |
Estimated variance of tau^ |

`VarSamp` |
Estimated variance component due to sampling aerial units |

`VarSight` |
Estimated variance component due to sighting process (i.e., series of binomial rv for each animal group) |

`Varmod` |
Estimated variance component due to estimating detection probabilities using test trial data |

John Fieberg

Rice CG, Jenkins KJ, Chang WY (2009). Sightability Model for Mountain Goats." The Journal of Wildlife Management, 73(3), 468- 478.

Steinhorst, R. K., and M.D. Samuel. (1989). Sightability adjustment methods for aerial surveys of wildlife populations. Biometrics 45:415-425.

Wong, C. (1996). Population size estimation using the modified Horvitz-Thompson estimator with estimated sighting probabilities. Dissertation, Colorado State University, Fort Collins, USA.

SightabilityModel documentation built on May 29, 2017, 9:37 p.m.

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