cswa {AHMbook}R Documentation

Point count and spot-mapping data for Chestnut-sided Warbler


Chestnut-sided Warblers (Setophaga pensylvanica) in 38 “wildlife openings” in the White Mountain National Forest were surveyed using point counts and spot-mapping during June and July 2004 as part of Richard Chandler's MS thesis. Counts are for birds detected by song at each point. Two of the larger openings had more than one point, giving 43 points in all. Surveys lasted 10 mins and were divided into intervals of (0–2], (2–5], and (5–10] min. Each point was surveyed 3 times, except for one point surveyed only twice. The spot-mapping data come from intensive surveys of each patch recording individual sightings and nest locations, and using counter-singing to separate adjacent territories.




cwsa is a list with 3 components:


a points x intervals x occasions array of counts; NAs correspond to the missing survey.


a data frame with rows for 43 points and the following columns:

  • time1 : time of start of first survey, hr; NA for the missing survey.

  • time2 : same for second survey.

  • time3 : same for third survey.

  • date1 : date of first survey, NA for the missing survey.

  • date2 : date of second survey.

  • date3 : date of third survey.

  • obs1 : observer ID for first survey.

  • obs2 : observer ID for second survey.

  • obs3 : observer ID for third survey.

  • patchArea : patch area, ha.

  • plotArea : size of point count area, ha. Most were 50-m radius but some were smaller because they overlapped adjacent forests which weren’t the focus of the study.

  • woodHt : woody vegetation height, m.

  • woodCov : proportion covered by woody vegetation.


a data frame with rows for 38 patches and the following columns:

  • CSWA : estimated population of chestnut-sided warblers in each patch obtained from spot-mapping.

  • parea : patch area, ha.


David King and colleagues.


Chandler, R.B., King, D.I., & Chandler, C.C. (2009) Effects of management regime on the abundance and nest survival of shrubland birds in wildlife openings in northern New England, USA. Forest Ecology and Management, 258, 1669-1676.

Chandler, R.B., Royle, J.A., & King, D.I. (2011) Inference about density and temporary emigration in unmarked populations. Ecology, 92, 1429-1435.

Kéry, M. & Royle, J.A. (2021) Applied Hierarchical Modeling in Ecology AHM2 - 2.



# Replace the NAs in the covariates with the mean from other surveys:
covs <- cswa$covs
covs$time1[is.na(covs$time1)] <- mean(covs$time1, na.rm=TRUE)
covs$date1[is.na(covs$date1)] <- mean(covs$date1, na.rm=TRUE)
# Now use covs instead of cswa$covs

[Package AHMbook version 0.2.9 Index]