# Trace element concentrations of barn swallow and willow warbler feathers --- The available dataset and R Script support the paper "Intra- and interspecific variation in trace element concentrations in feathers of North European Trans-African migrants", which will be published by the Journal of Avian Biology (2023). It contains the raw data in CSV format, as well as the R script that was written for the analysis. We studied the variation of 18 different trace elements in feathers of two long-distance Trans-African migrants, willow warblers Phylloscopus trochilus and barn swallows Hirundo rustica, using body feathers of museum specimens of birds from Finnish breeding grounds. The trace elements were measured using Laser-Ablation Inductively-Coupled-Plasma Mass-Spectrometry. ## Description of the data and file structure The uploaded files are the following: Trace_element_feathers.csv: this is the dataset that contains the information used in the paper's analyses. Each row referst to a measurement spot along a feather's rachis. The columns contain the following information: * The concentration of each of the 18 elements analysed in the paper * An identifier for the feather to which the measurement spot belongs * An identifier for the individual to which the feather belongs * Season during which the feather was collected (spring / autumn) * Species to which the feather belonged (barn swallow / willow warbler) * Number of the measurement spot along the rachis ## Sharing/Access information The data are currently only available at Dryad. For more information feel free to email the corresponding author. ## Code/Software Trace_element_feathers_analysis.R: this is an R file that should open the script containing our analyses. The workflow roughly follows the paper, and it is divided into sections: 1. Data import 2. Data cleaning and formatting 3. Modelling 4. Plotting