ReadMe for Size-dependent costs of migration: migrant bird species are subordinate to residents in aggressive contests, but only at small body sizes This readme file describes the variables in the two data files (rangewide_dataset.csv and sitespecific_dataset.csv) that were the basis of the above manuscript. Variables in the two datasets are identical, with the exception of the variable "observation.period" which is found in sitespecific_dataset.csv only. The order of species pairs follows the taxonomic order of Gill and Donsker (2016) for the behaviourally dominant species. For any further queries please contact: Paul Martin (pm45@queensu.ca) comparison = comparison number animal = genus (or numbered clade within genus for Oenanthe) corresponding to independent clades in the phylogeny (see R code); used in MCMCglmm analyses; na refers to species pairs that were not phylogenetically independent (i.e., the two interacting species represented different phylogenetically independent clades that were already present in the analysis) animal.phylo = genus (or sequentially lettered genus for lineages with multiple observations per lineage) corresponding to independent clades in the phylogeny (see R code); used in phyloglm analyses; na refers to species pairs that were not phylogenetically independent (i.e., the two interacting species represented different phylogenetically independent clades that were already present in the analysis) tax.order = taxonomic order of the interacting species pair (following Gill and Donsker 2016) tax.family = taxonomic family of the interacting species pair (following Gill and Donsker 2016) dom.genus = taxonomic genus of the behaviourally dominant species (following Gill and Donsker 2016) dom.species = taxonomic species of the behaviourally dominant species (following Gill and Donsker 2016) dom.status = whether the behaviourally dominant species migrates (migrant) or does not (resident) sub.genus = taxonomic genus of the behaviourally subordinate species (following Gill and Donsker 2016) sub.species = taxonomic species of the behaviourally subordinate species (following Gill and Donsker 2016) sub.status = whether the behaviourally subordinate species migrates (migrant) or does not (resident) pattern = relationship between migration and dominance (1=resident species was dominant; 0=resident species was subordinate) dom.win = number of aggressive interactions between the behaviourally dominant and subordinate species that were won by the dominant species; na refers to species pairs where quantitative data on aggressive contests were not available sub.win = number of aggressive interactions between the behaviourally dominant and subordinate species that were won by the subordinate species; na refers to species pairs where quantitative data on aggressive contests were not available sum.win = total number of aggressive interactions observed between species (i.e., dom.win + sub.win); na refers to species pairs where quantitative data on aggressive contests were not available n.weights = For species pairs where aggressive interaction data were accessible, weights = ln(sum.win). For species pairs where aggressive interaction data were not accessible (i.e., sum.win = 'na'), weights = 1. Used in binomial glms to weight data by our confidence in dominance relationships. binom.test = P value from a binomial test on the proportion of wins by the dominant species out of the total number of aggressive interactions between species (i.e., sum.win); binomial tests were run in the program R (binom.test; R Core Team 2016); na refers to species pairs where quantitative data on aggressive contests were not available prop.win = the proportion of aggressive contests between species that were won by the dominant species (i.e., dom.win/sum.win); na refers to species pairs where quantitative data on aggressive contests were not available observation.period = the period (breeding, wintering, migration, post-breeding, unspecified) during which aggressive interactions were recorded between the focal species, from the perspective of the migrant species (this variable is in the sitespecific_dataset.csv data file only) dom.mass = mass in grams of the behaviourally dominant species (averaged between males and females when source data distinguished between sexes) sub.mass = mass in grams of the behaviourally subordinate species (averaged between males and females when source data distinguished between sexes); na refers to species where mass data were not available dom.heavier = whether (value of 1) or not (value of 0) the behaviourally dominant species was heavier than the behaviourally subordinate species, based on values in columns dom.mass and sub.mass; note: for one species (Ardea humbloti) we could find no mass data, and thus we estimated the difference in sizes between the resident and migrant species in this comparison using wing chord (in mm) (see details in "mass.data.reference" cell for this species pair) res.minus.migr.mass = [(mass of the resident species in g) - (mass of the migrant species in g)]/(average of the masses of the resident and migrant species in g); note: for one species (Ardea humbloti) we could find no mass data, and thus we estimated the difference in sizes between the resident and migrant species in this comparison using wing chord (in mm) (see details in "mass.data.reference" cell for this species pair) resident.heavier = whether (=1) or not (=0) the variable res.minus.migr.mass was greater than zero (and thus the resident species was heavier than the migrant species) ave.mass = average mass in grams of the dominant species (dom.mass) and subordinate species (sub.mass) migr.mass = mass in grams of the migrant species (averaged between males and females when source data distinguished between sexes) migr.species = name (genus species) of the migrant species in each comparison br.lat = centroid (area-weighted mean) latitude of the breeding range of the migrant species in decimal degrees br.long = centroid (area-weighted mean) longitude of the breeding range of the migrant species in decimal degrees wn.lat = centroid (area-weighted mean) latitude of the wintering range of the migrant species in decimal degrees wn.long = centroid (area-weighted mean) longitude of the wintering range of the migrant species in decimal degrees interaction.data.reference = the reference(s) for data on behavioural dominance between the species pair mass.data.reference = the reference(s) for data on mass for the species pair phylogenetic.relationship.reference = the reference(s) for phylogenetic relationships for each genus References Gill, F., and D. Donsker, eds. 2016. IOC World Bird List (v 6.2). Available online at http://www.worldbirdnames.org. R Core Team. 2016. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. URL http://www.R-project.org/.