WBPHStidy: Calculate index estimates for specified WBPHS count and...

In USFWS/AKaerial: Analysis of Alaska Region Aerial Survey Data

Calculate index estimates for specified WBPHS count and transect data

Description

WBPHStidy uses annual WBPHS adjusted count data and flown transects to calculate an index estimate using a ratio estimator

Usage

WBPHStidy(adj, flight)

Arguments

adj	Adjusted counts for a given year of the WBPHS survey (see ReadWBPHS)
flight	Flight summary for a given year of the WBPHS survey (see SummaryWBPHS)

Details

WBPHStidy provides a method for creating an annual index estimate for the WBPHS survey. Individual observations and sampled areas are summed first at the transect level. Groups are created for eiders, mergansers, scoters, and grebes that pool species as:

1. Eider COEI, KIEI, SPEI, STEI, UNEI

2. Merganser COME, RBME, UNME

3. Scoter BLSC, SCOT, SUSC, WWSC

4. Grebe HOGR, RNGR, UNGR

Transect-level counts are summarized at the stratum level to produce densities of index groupings and variance according to the classic ratio estimator (Cochran 1977), then index estimates are adjusted according to historical visual correction factors (VCFs, see WBPHS_VCF) in an attempt to correct for incomplete detection.

Value

Data frame of counts, densities, areas, index estimates, and adjusted index estimates.

Author(s)

Charles Frost, [e-mail]

References

https://github.com/USFWS/AKaerial

USFWS/AKaerial documentation built on April 3, 2025, 4:06 p.m.