Short-term dietary changes are reflected in the cerebral content of adult Ring-billed Gulls

Long-chain omega-3s (n3-LCPUFAs) are produced primarily in aquatic ecosystems and are essential for the structural integrity of vertebrates’ brains. Carnivorous mammals must consume n3-LCPUFAs throughout their lifespan to maintain optimal cerebral functions; it is unknown whether other taxa are under similar nutritional pressures. This is concerning because many avian predators now rely on anthropogenic foods lacking n3-LCPUFAs. Here, we tested whether a recent or longer-term diet explains the encephalic fatty acid composition of a seabird, the Ring-billed Gull, that now thrives in cities. During the breeding season, rural gulls exploiting marine organisms had significantly higher encephalic levels of n3-LCPUFAs (mean±SD: 32±1%) than city-nesting gulls exploiting garbage (27±1%). Stable isotope analysis of blood and feathers grown during different seasons showed that urban and rural nesters consumed similar fall and winter diets, suggesting that the difference in cerebral n3-LCPUFA of b..., , , # Short-term dietary changes are reflected in the cerebral content of adult Ring-billed Gulls

[https://doi.org/10.5061/dryad.5x69p8dc5](https://doi.org/10.5061/dryad.5x69p8dc5)

## Description of the data and file structure

### Dataset 1: Lamarre\_Wilson\_2024\_main\_data

Contains data regarding ring-billed gulls' breeding colonies, treatment groups, and biomarkers (stable isotopes and fatty acids). Used to establish whether short-term dietary supplementation and long-term diet were reflected in the composition of the brains of adults.

**VERSION CHANGES:** Changes between version 1 and version 2 of the dataset: The name of the file has been updated from Lamarre_Wilson_2024_RSOS_rawdata.csv to Lamarre_Wilson_2024_main_data.csv

### Dataset 2: siber\_isotope

Stable isotope data used specifically to work with the SIBER package in R

| Spreadsheet 1: Lamarre\_Wilson\_2024\_main\_data | ...