Savannah_sparrow_1980 {Distance}

Savanna sparrow point transects

Description

Point transect data collected in Colorado 1980/81 to examine effect of agricultural practices upon avian community.

Format

data.frame with 468 observations (1980) and 448 observations (1981) of 7 variables:

• Region.Label stratum label (pasture ID)

• Area stratum area (set to 1 so density is reported)

• Sample.Label transect identifier

• Effort number of visits

• object object ID

• distance radial distance (m)

• Study.Area name of study area

Details

Design consisted of point transects placed in multiple pastures (3 in 1980 and 4 in 1981). While many species were observed, only data for Savannah sparrows (Passerculus sandwichensis) are included here.

Data given here are different from the Distance for Windows example project. Here each individual sighting is treated as an independent observation. This corresponds to the analysis in Buckland et al. (2001) Section 8.7. In the Distance for Windows project objects are clusters of individuals. This should not affect the results too greatly as most clusters were of size 1, and so the results obtained should not be too far out.

References

Knopf, F.L., J.A. Sedgwick, and R.W. Cannon. (1988) Guild structure of a riparian avifauna relative to seasonal cattle grazing. The Journal of Wildlife Management 52 (2): 280–290. doi:10.2307/3801235