Data for: Intra- and interspecific variation in trace element concentrations in feathers of North European Trans-African migrants

The knowledge of migratory connectivity is important for understanding the potential drivers of populations and it is thus important for conservation implications. Migratory connectivity of species can be studied using exogenous, such as rings and transmitters, or endogenous markers, such as stable isotopes and trace elements. The use of trace elements has been much less frequently studied compared to stable isotopes. Trace elements can be studied from the feathers of birds and this does not necessarily require trapping of individuals. Here 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. We show that trace element concentrations were relatively stable along the rachis withi..., 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).
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:

A running index
An indication of which spot is being measured
The concentration of each of the 20 elements analysed for the paper at the given spot
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
A code for the individual (same informati..., Trace_element_feathers.csv can be opened with a wide variety of programmes, such as Microsoft Excel, LibreOffice Calc or R. It is a CSV file that uses commas as separators, points as decimal separators and has a header line. Missing values are represented by \"NA\".
Trace_element_feathers_analysis.R can be opened with R or RStudio.