Diet, habitat, and flight characteristics correlate with intestine length in birds

It is often assumed that there is a link between diet and the dimensions of the avian intestinal tract. Typically, species that feed on hard-to-digest items have longer intestines, the opposite being true for species that consume highly digestible diets. However, few studies tested this hypothesis. Here, we collated data on the length of intestinal sections and body mass of 390 bird species and tested various relationships with diet, climate, and locomotion proxies. There was a strong phylogenetic signal in all datasets. The total and the small intestine scaled more than geometrically (95%CI of the scaling exponent excluding 0.33). The traditional dietary classification (faunivore, omnivore, herbivore) had no significant effect on total intestine length. Significant dietary proxies included %folivory, %frugi-nectarivory, and categories (frugi-nectarivory, granivory, folivory, omnivory, insectivory, and vertivory). Individual intestinal sections were affected by different dietary proxies..., , , , # Data from: Diet, habitat, and flight characteristics correlate with intestine length in birds

Dataset DOI: [10.5061/dryad.v15dv41z2](10.5061/dryad.v15dv41z2)

## Description of the data and file structure

Data on bird intestinal length were collated as original data (BirdIntestine_Data.xlsx, first sheet) from the literature (BirdIntestine_Data_References.docx). Subsequently, weighted averages were calculated per species for each intestinal section separately, and supplemented with species-specific biological information (BirdIntestine_Data.xlsx, second sheet). The key spreadsheet contains the description of all the variables included. Empty cells represent missing data.

Data was collected from two sources: scientific publications or through necropsies performed by the co-authors. Data were manually extracted from the publications. Data from published sources were only used if the publication included the species, body mass (kg), and length (cm) of the intestinal tract. If the lit...