DOI: 10.5061/dryad.95x69p8tc
title: Data for: Improving population size estimation at Western Capercaillie leks: lek counts vs. genetic methods

description: The Western Capercaillie (Tetrao urogallus), hereafter capercaillie, is
 the largest galliform bird present in the boreal and montane forests of
 the Western Palearctic. Precise and accurate methods for estimating the
 number of individuals and/or their densities are crucial for the proper
 management of its free-ranging populations. However, obtaining reliable
 estimates of the abundance of populations of wild species and,
 particularly, of birds is not a simple task. In the case of lek-mating
 birds such as capercaillie, surveys are traditionally based on lek counts,
 that is, counts of calling males present in their mating areas: the leks.
 This study was carried out on the Pyrenees at six capercaillie leks where
 two different lek counting approaches were performed: hide-based and
 walk-based. The results were compared with those obtained from an estimate
 of minimum population size (MPE) derived from genotyping all faeces
 samples found in the lek area, and with a population size estimate derived
 from a genetic mark-recapture model (N ̂) of each capercaillie lek. The
 results of N ̂ were used to estimate the detection rate (D) of both lek
 count approaches. Our results show that traditional lek counts do not
 detect all male capercaillies since the detection rate was 0.34 (95% CI:
 0.26-0.43) for hide- and 0.56 (95% CI: 0.43-0.68) for walk-based lek
 counts. Our results suggest that the walk-based lek counts were more
 efficient than the hide-based ones, providing more accurate results
 compared to the N ̂ estimate. The combination of non-invasive sampling
 with the genetic mark-recapture model was found to be the most reliable
 method for obtaining the N ̂ of leks given that traditional lek counts
 underestimate the number of capercaillies and, furthermore, can cause
 disturbance to the species at these sites.
description: To estimate the population size (N)<strong>
 </strong>of each lek, we use only the male samples that have been
 correctly analysed i.e., with a QI&gt;0.6. We used
 the Bayesian approach of this classical M<sub>0 </sub>model,
 in which the model is implemented in JAGS code (Plummer 2003) using data
 augmentation (Kéry and Schaub 2012, Chapter 6.2.1). This model estimated
 the detection probability on all three sampling occasions based on the
 assumption that all individuals in each sampling session have equal
 detection probabilities (see Otis et al., 1978, Kéry and Schaub, 2012 and
 Supplementary Material S1 for more details and see the Otis Mo model code
 in R).
 <strong>References:</strong> Kéry,
 M. and Schaub, M. 2012. Bayesian population analysis using WinBUGS. A
 hierarchical perspective. First edition. - Academic Press.
 Otis, D.L., Burnham, K. P., White, G. C. and Anderson, D. R.
 1978. Statistical inference from capture data on closed animal
 populations. – Wildl. Monogr. 62:3–135. Plummer, M.
 2003. JAGS: a program for analysis of Bayesian graphical models using
 Gibbs sampling. Proceedings of the International Workshop on Distributed
 Stat. Comput. 3:124.
description: # Data for: Improving population size estimation at Western Capercaillie
 leks: lek counts vs. genetic methods The databases provide the date of
 each sampling season and the number of individuals genotyped with the
 number of times each individual has been sampled within each sampling
 session. We provide our data in nine databases (the different leks)
 ready-to-use databases by loading them into the R functions in
 Supplementary Material S1 for the Otis M0 model. The databases are:
 AND1-2018.xlsx survey: 2018-1 AND1-2019.xlsx survey: 2019-1 AND2-2007.xlsx
 survey: 2017-2 T10-2018.xlsx survey: 2018-2 T17-2016.xlsx survey: 2016-1
 T18-2016.xlsx survey: 2016-2 T19-2016.xlsx survey: 2016-3
 T20-2016.xlsx survey: 2016-4 T20-2017.xlsx survey: 2017-1 Abbreviations of
 the database: date: date the sample was collected (faeces) indv: label of
 the genotyped individual An additional database is: Y_capercaille.xlsx
 This database is a summary of the samples counting for the whole nine leks
 in each sampling session. For each lek and year, we specify for each one
 of the three sampling occasions the number of male samples collected and
 used for the population estimate (i.e. with a QI&gt;0.6). the column total
 is the sum of the number of samples and the column Population buffer is
 the theoretical maximal number of individuals that could be present at
 most in each lek, this number is used for the flange M0 estimator.