DOI: 10.5061/dryad.1vhhmgr4g
title: Data from: Dressed for the weather: Tawny owl feather adaptations across a climatic gradient

description: Populations are presumed to be adapted to local environmental conditions
 via natural selection, with gene flow breaking up local adaptations. In
 birds, several aspects of feathers may reflect local adaptation; the
 insulation capacity of feathers may be greater in cold regions, and
 colouration, as darker feathers absorb more heat compared to
 lighter-coloured feathers. We studied feather properties (plumulaceous
 part of the feather, density of barbs and barbules) of tawny owls across
 nine populations covering a large part of the species’ European range
 (9-52 individuals per population) as well as their plumage colour, scored
 as dark (brown) vs light (grey) morphs. We compared these traits'
 phenotypic divergence (PST) with the divergence expected based on genetic
 drift (FST) inferred using eight microsatellites. The FST was low (0.022;
 95% CI 0.005-0.039), and most feather structures' phenotypic
 divergence (PST) exceeded the FST. However, phenotypic divergence in
 plumage colour was low and not significant, implying a limited role of
 natural selection in shaping variation in plumage colouration at large
 spatial scales. Between-population differentiation in feather properties
 was more pronounced in chest feathers than back feathers. In colder
 populations, the plumulaceous part of the back, but not the chest, was
 larger (implying greater insulation). Although proper evaluation hinges on
 understanding how insulative properties confer a fitness advantage in a
 given environment, our findings imply that properties of avian feathers
 may reflect local adaptation, possibly related to climate.
description: # Data from: Dressed for the weather: Tawny owl feather adaptations across
 a climatic gradient
 [https://doi.org/10.5061/dryad.1vhhmgr4g](https://doi.org/10.5061/dryad.1vhhmgr4g) ## Description of the data and file structure Datasets for the manuscript "**Dressed for the weather: Tawny owl feather adaptations across a climatic gradient**". Data was collected from tawny owls' feathers (length of the feather, length of the plumulaceous part) and from microscope pictures (barbs and barbules number per cm or mm). File list * meantempmeanprec.csv * plot_prop_variance.csv * Barbules.csv * Barbs.csv * measures2023clean3.csv File description * meantempmeanprec.csv: Mean temperature and precipitation for each winter month in each country of the study. Includes the country, the month, the mean temperature in degrees Celsius, and the mean precipitation in mm. * plot_prop_variance.csv: proportion of variance explained by the length of the plumulaceous part of the chest, the back, the number of barbs of the chest and back, the number of barbules of the chest and back, and the morph associated with the se. This data set also includes the category (cat) of the measure "plu" for plumulaceous length, "barb" for barb, "barbule" for barbule, and "individual" for the morph, and the feather column indicates for the chest or back. This table was used to make Figure 5. * Barbules.csv: number of barbules per mm, includes the owl id, the picture id, the feather type (back or chest), the number of barbs, the country, the morph (G for grey, B for brown), the sex (F for female, M for male, U for unknown), the year of collection, the researcher id, if the picture was matching the exact measurement (0 for no, 1 for yes). * Barbs.csv: number of barbs per cm, includes the owl id, the picture id, the feather type (back or chest), the number of barbs, the country, the morph (G for grey, B for brown), the sex (F for female, M for male, U for unknown), the year of collection, the researcher id, if the picture was matching the exact measurement (0 for no, 1 for yes). * measures2023clean3.csv: measures of the feather length. Includes: the country, the year of collection, the owl id, the morph (G for grey B for brown), the sex (F for female, M for male, U for unknown), the picture id, the researcher, the feather length in cm, the plumulaceous length in cm and if the picture was an exact match for the measurement (0 for no, 1 for yes). All the "NA" values in the files stand for "Not available" values.