Skeletal traits for thousands of bird species v1.0

The dataset spans 2,057 species of birds (Aves: Passeriformes) and
includes linear measurements of 12 skeletal elements from 14,419
individuals. In addition to the trait values directly measured from
photographs, we leverage the multi-dimensional nature of our dataset and
known phylogenetic relationships of the species to impute missing data
under an evolutionary model. The traits included in the dataset are: the
lengths of the tibiotarsus, humerus, tarsometatarsus, ulna, radius, keel,
carpometacarpus, 2nd digit 1st phalanx, furcula, and femur; the maximum
outer diameter of the sclerotic ring, and the length from the back of the
skull to the tip of the bill (treating the rhamphotheca as part of the
bill when it remains present on the specimen). These data are presented in
three ways: 1) a dataset that only includes trait estimates for elements
that were confidently identified and measured, 2) a complete
specimen-level dataset that includes imputed trait values for all missing
data, and 3) a species-mean dataset based on a model of trait evolution
that includes estimates of the species mean, species-level standard error,
variance, and 95% confidence interval of the trait estimates.