Replication data for "Daytime songbird migrants at sea: the influence of coastal proximity on abundance"

SAS songbirds Abstract Human activities at sea, including offshore energy development, along with environmental changes, are altering marine ecosystems. Their impact on land-based migratory species crossing marine areas remains poorly understood. Songbirds frequently traverse even remote ocean areas, facing risks such as drowning at sea and interactions with man-made structures. Yet, their spatial distribution at sea, critical for assessing potential threats, remains largely unquantified. Using a 30-year dataset of ship-based observations, we map the large-scale marine distribution of mainly daytime songbird migrants in German waters. Despite their regular offshore occurrence, even in large flocks, migration intensity declined with increasing distance from the coast and consistently across regions (North and Baltic Sea), seasons (spring and autumn), and the abundant species. Due to observational challenges, nighttime migrants are underrepresented, but we assume a similar distribution pattern. When integrated with radar surveys, individual tracking, and phenological data, these insights inform conservation strategies as offshore developments expand. Content Data data/: Contains processed data files and geographic data. shp/: Shapefiles used in the analysis. raw_data/: Raw observation and effort data. birds_all.gpkg:Processed data containing total bird counts per 10x10 km grid cell. birds_sp.gpkg: Processed data containing bird counts for the four most frequent species per 10x10 km grid cell. birds_groups.gpkg: Processed data containing bird counts per season and migration type for each 10x10 km grid cell. species.csv: Species codes and migration types. Code main.R: Run the complete analysis pipeline. R/: Contains all the R code to run the analysis. _setup.R: Configure the project environment. _utils.R: Utility functions. 1_data_preparation.R: Code for rasterizing and processing observation data. 2_modelling.R: Code to run the models and extract results. Documentation vignettes/: Contains vignettes for the analysis. supplement.qmd: Supplementary materials. Manuscript index.qmd: Manuscript source file. references.bib: Bibliography database file. figures/: Contains visual assets that are embedded in the manuscript. results/: Contains data objects generated by the research pipeline. overview.csv: Data overview table of observations.. Utility bibtexDOI.sh: Bash script that fetches the BibTeX entry for a given DOI and appends it to the project bibliography file. Reproducibility This project was conducted with R 4.5.2 and leverages renv to ensure a reproducible R environment. The renv package captures and restores the exact package versions used in this analysis, enabling others to recreate the environment precisely. Download this archive or clone the Git repository: git clone https://codeberg.org/migecol/sas_songbirds Open the project in your preferred editor. In the project’s working directory, restore the environment using renv: install.packages("renv") renv::restore() When prompted, select “1: Activate the project and use the project library”. This will install all required packages as specified in the renv.lock file. Run the analysis.