unmarked is an R package available for download from CRAN that fits hierarchical models of animal abundance and occurrence to data collected using survey methods such as point counts, site occupancy sampling, distance sampling, removal sampling, and double observer sampling. Documentation comes with the package. The following R code will install the package and open some of the help files.

install.packages("unmarked")   # Download the package. You might need to choose a CRAN mirror
library(unmarked)              # load the package
?unmarked                      # general help page
?occu                          # help page for the single-season site occupancy model
vignette("unmarked")           # document describing the package with example R code
vignette("distsamp")           # distance sampling analysis in unmarked
vignette("colext")             # dynamic occupancy models in unmarked 

To cite the package in publication, please reference:

Fiske, I. and R.B. Chandler. 2011. unmarked: An R package for fitting hierarchical models of wildlife occurrence and abundance. Journal of Statistical Software, 43(10), 1-23. URL http://www.jstatsoft.org/v43/i10/.

The purposes of this site are to provide users with additional information, post answers of frequently asked questions, share files, allow users to test pre-release versions, and provide links to related sites.

If you want to edit this site or help with the package development, contact Richard Chandler (rchandler@usgs.gov). All other questions should be submitted to the users' group.