caribou (version 1.1-1)

petersen: Lincoln-Petersen estimator for caribou abundance

Description

The function petersen estimates the total population size based on the Lincoln-Petersen Index as applied to radio telemetry data by White and Garrott (1990). It uses the Lincoln-Petersen estimator with Chapman's (1951) bias correction and the bias corrected standard error estimator of Seber (1970) and Wittes (1972).

Usage

petersen(mat, M, S = 0)
# S3 method for petersen
print(x,…)

Arguments

mat

A matrix containing in the first column the number of radio-collared animals in the detected (photographed) groups and in the second column the corresponding size of the detected groups.

M

A numeric: the total number of active collars during the census (equivalent to the argument n in the function abundance).

S

A numeric: the minimum size that define well aggregated groups. Only observations from well aggregated groups (containing at least S animals) are taken into account in the computation. The default is zero (every observation is included in the computation).

x

An object, produced by the petersen function, to print.

…

Further arguments to be passed to methods (see print.default).

Value

G

The number of well aggregated groups.

R

The total number of radio-collared animal observed in the well aggregated groups.

C

The total number of animals observed in the well aggregated groups containing at least one radio-collared animal during the survey.

T.hat

The modified lincoln-Petersen estimator for the total number of animals in a herd.

se_T.hat

The estimated standard error of LP_T.hat.

mat_aggre

A matrix containing a subset of the input matrix mat: the data for the well aggregated groups only.

call

The function call (object of class "call").

References

Chapman, D. G. (1951). Some properties of the hypergeometric distribution with applications to zoological sample censuses. University of California Publications in Statistics, 1(7), 131-160.

Seber, G.A.F. (1970). The effects of trap response on tag recapture estimates. Biometrics, 26, 13-22.

White, G.C. and Garrott, R.A. (1990). Analysis of wildlife radio-tracking data. San Diego: Academic Press.

Wittes, J.T. (1972). On the bias and estimated variance of Chapman's two-sample capture-recapture population estimate. Biometrics, 28, 592-597.

See Also

abundance

Examples

# NOT RUN {
data(GRH93)
petersen(GRH93, M=92) # default S=0
petersen(GRH93, M=92, S=4000)
# }