petersen {caribou}

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 class '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").

Author(s)

Louis-Paul Rivest [e-mail] and
Helene Crepeau [e-mail] and
Serge Couturier [e-mail] and
Sophie Baillargeon [e-mail]

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

data(GRH93)
petersen(GRH93, M=92) # default S=0
petersen(GRH93, M=92, S=4000)