Genetic mark-recapture analysis of winter faecal pellets allows estimation of population size in sage grouse Centrocercus urophasianus

Sex ratio, and the extent to which it varies over time, is an important factor in the demography, management, and conservation of wildlife populations. We estimated pre-breeding sex ratio of greater sage-grouse (Centrocercus urophasianus) in a peripheral, geographically isolated population in northwestern Colorado during two consecutive winters using closed-population, robust-design, multi-state, genetic mark-recapture models in program MARK (White and Burnham 1999). This data release includes the data files (.inp format) used in those models, as described in Shyvers et al. 2023. The data include capture histories and auxiliary data for individual greater sage-grouse collected during two study seasons: Season 1 (winter 2012-2013) and Season 2 (winter 2013-2014) and are readable using program MARK or notepad. Each data row includes the unique bird identification number (GMR-ID); the bird’s encounter history for n= sampling occasions coded as a static state (M = male, F = female); the group ID; and a region covariate (0 = North, 1 = South). The data were adapted from those originally developed for Shyvers et al. 2020 and applied using Closed Robust Design Multi-state (CRDMS) Huggins' p and c w/state probabilities in program MARK to obtain estimates of Omega, enabling estimation of sex ratio with associated confidence intervals (see Shyvers et al. 2023).

References:

Shyvers, J.E., Walker, B.L., Oyler-McCance, S.J., Fike, J.A. and Noon, B.R. 2023. Genetic mark-recapture analysis reveals large annual variation in pre-breeding sex ratio of greater sage-grouse. Wildlife Biology (https://doi.org/10.1002/wlb3.01085)

Shyvers, J.E., Walker, B.L., Oyler‐McCance, S.J., Fike, J.A. and Noon, B.R., 2020. Genetic mark-recapture analysis of winter faecal pellets allows estimation of population size in Sage Grouse Centrocercus urophasianus. Ibis, 162(3), pp.749-765.

White, G. C., and K. P. Burnham. 1999. Program Mark: survival estimation from populations of marked animals. – Bird Study 46:120–139.