Let’s assume the study area on which these transects were collected was 300 ha. Estimates of sparrow density on the sampled transects and sparrow abundance in the study area are obtained by calling the abundEstim function with an estimate distance function, transect data frame, and study area size. Measurement units must be applied to study area size so that Rdistance computes density correctly. By default, Rdistance computes 95% confidence intervals by bootstrap resampling individual transects in the transect information data frame. Setting showProgress to FALSE shuts off the progress bar. Outside of markup documents, the bootstrap progress bar can improve sanity of the analyst.