DOI: 10.5061/dryad.mw6m9067z
title: Data from: Comparative evaluation of noninvasive DNA sampling and line transect surveys for spring density estimation of black grouse and capercaillie

description: Reliable abundance estimates provide essential information in ecology,
 conservation, and management of many wild grouse populations. In this
 3-year study, we comparatively evaluate the suitability of traditional
 line transect distance sampling of flushed birds versus a spatial
 capture-recapture survey with noninvasive DNA samples for individual
 identification to estimate spring densities of black grouse and
 capercaillie in a ~30 km2 boreal forest area in central Norway. The number
 of observed flushed birds during each field survey period and survey year
 was low, and did not allow for reliable estimation of abundance from
 distance sampling in any of the three years, with a total search effort of
 745 km. Collection of noninvasive DNA samples and spatial
 capture-recapture models provided absolute spring density estimates of 1.6
 and 2.3 black grouse km-2 in two out of three survey years, and 0.7
 capercaillie km-2 in one out of three survey years. Spring population
 surveys based on a collection of noninvasive DNA samples in a boreal
 forest habitat could be a better alternative to traditional line transect
 surveys based on distance sampling of flushed birds in estimating
 abundance for black grouse and capercaillie, but rely on a sufficient
 number of unique individuals captured and recaptured at different spatial
 locations.
description: # Comparative evaluation of noninvasive DNA sampling and line transect
 surveys for spring density estimation of black grouse and capercaillie
 Dataset DOI: [10.5061/dryad.mw6m9067z](10.5061/dryad.mw6m9067z) ##
 Description of the data and file structure The dataset contains six input
 files for the spatial capture-recapture models analysed  with function of
 the package ‘secr’ (ver. 3.1.0, Efford 2017) in an R environment (ver.
 3.4.2, R Core Team 2017). The “trapfile2012_black grouse.txt”,
 “trapfile2013_black grouse.txt” and “trapfile2012_capercaillie.txt”
 contains the detector arrays. The “captures2012_black grouse.txt”,
 “captures2013_black grouse.txt” and “captures 2012_capercaillie.txt”
 contains the detection of individuals at different detectors. A null model
 (ɡ0 and σ constant) was fitted from which density estimates was derived.
 Efford, M. G. 2017. secr: Spatially explicit capture-recapture models. R
 package version 3.1.0.
 [https://CRAN.R-project.org/package=secr](https://CRAN.R-project.org/package=secr). R Core Team. 2017. R: A language and environment for statistical computing. -  R version 3.4.2. R Foundation for Statistical Computing. Vienna, Austria, R Foundation for Statistical Computing. Vienna, Austria. ### Files and variables #### File: captures2012\_black\_grouse.txt **Description:** contains columns with data on "year", "animal_id", "day" of capture and "trap_id" of capture for black grouse in 2012. ##### Variables * year: year * animal_id: animal identifier * day: capture day of the year * trap_id: trap identifier for capture #### File: captures2012\_capercaillie.txt **Description:** contains columns with data on "year", "animal_id", "day" of capture and "trap_id" of capture for capercaillie in 2012 ##### Variables * year: year * animal_id: animal identifier * day: capture day of the year * trap_id: trap identifier for capture #### File: captures2013\_black\_grouse.txt **Description:** contains columns with data on "year", "animal_id", "day" of capture and "trap_id" of capture for black grouse in 2013. ##### Variables * year: year * animal_id: animal identifier * day: capture day of the year * trap_id: trap identifier for capture #### File: trapfile2012\_black\_grouse.txt **Description:** contains columns with data on "trap_id", "x"- and "y" coordinates of the trap in WGS84 UTM33North, and trapping sessions indicating if the trap was active (1) or not (0) for black grouse in 2012. ##### Variables * trap_id: trap identifier * x: x-coordinates in WGS84, UTM zone 33N * y: y-coordinates in WGS84, UTM zone 33N * occ1:sampling session 1 * occ2:sampling session 2 * occ3:sampling session 3 * occ4:sampling session 4 * occ5:sampling session 5 * occ6:sampling session 6 #### File: trapfile2012\_capercaillie.txt **Description:** contains columns with data on "trap_id", "x"- and "y" coordinates of the trap in WGS84 UTM33North, and trapping sessions indicating if the trap was active (1) or not (0) for capercaillie in 2012. ##### Variables * trap_id: trap identifier * x: x-coordinates in WGS84, UTM zone 33N * y: y-coordinates in WGS84, UTM zone 33N * occ1: sampling session 1 * occ2: sampling session 2 * occ3: sampling session 3 * occ4: sampling session 4 * occ5: sampling session 5 * occ6: sampling session 6 #### File: trapfile2013\_black\_grouse.txt **Description:** contains columns with data on "trap_id", "x"- and "y" coordinates of the trap in WGS84 UTM33North, and trapping sessions indicating if the trap was active (1) or not (0) for black grouse in 2013. ##### Variables * trap_id: trap identifier * x: x-coordinates in WGS84, UTM zone 33N * y: -coordinates in WGS84, UTM zone 33N * occ1:sampling session 1 * occ2:sampling session 2 * occ3:sampling session 3 * occ4:sampling session 4 * occ5:sampling session 5 * occ6:sampling session 6 * occ7:sampling session 7 * occ8:sampling session 8 * occ9:sampling session 9 * occ10:sampling session 10 * occ11:sampling session 11 * occ12:sampling session 12 ## Code/software R Core Team. 2017. R: A language and environment for statistical computing. -  R version 3.4.2. R Foundation for Statistical Computing. Vienna, Austria, R Foundation for Statistical Computing. Vienna, Austria. Efford, M. G. 2017. secr: Spatially explicit capture-recapture models. R package version 3.1.0. [https://CRAN.R-project.org/package=secr](https://CRAN.R-project.org/package=secr).