Fitting detection functions to line transect data

Estimating density of duck nests

The data are the famous “ducknest” data similar to those data described in (Anderson & Pospahala, 1970). Data exist within the Distance package, so emphasis will be upon performing analysis rather than acquiring data.

You will do some exploratory analysis of the detection distances, then use the function ds() to fit detection functions to the data. You’ll also use the function convert_units() for properly dealing with different units of measure in the data.

The estimated detection functions will be plotted and assessed for goodness of fit.

Lecture materials

Lecture discussion

Slides

Video

Exercise materials

Using R package

Video introduction

Instructions

Solution and discussion

Video summary

Using Distance for Windows

Video introduction

Instructions

Solution and discussion

Video summary

Supplemental materials

Effect of truncation upon density estimates

Demonstration of changing truncation distance

References

Anderson, D. R., & Pospahala, R. S. (1970). Correction of bias in belt transect studies of immotile objects. The Journal of Wildlife Management, 34(1), 141–146. https://doi.org/10.2307/3799501