Diet, phenology, and body size shape nutrient release by songbirds

Animals can dramatically alter ecosystem structure and function through the cycling and transport of nutrients in their waste. While birds are particularly capable of influencing nutrient cycles due to their high mobility, abundance, metabolism, and functional diversity, the factors shaping variation in nutrient release among birds remain poorly understood. 
We examined how trophic position, phenology, and body size shape the release of carbon (C), nitrogen (N), and phosphorus (P) in the waste of a diverse assemblage of songbirds. We analyzed waste samples (reflecting excretion and egestion) from 151 individual songbirds (31 species) at a migratory stopover site during one spring and one fall season in upstate New York, USA. 
Trophic position, represented by δ15N in waste, correlated positively with %N and negatively with C:P. Waste stoichiometry also differed between seasons with higher %N and lower C:N in spring compared to fall as birds shifted their diets from N-rich insec..., , # Diet, phenology, and body size shape nutrient release by songbirds

Dataset DOI: [10.5061/dryad.jq2bvq8q6](https://doi.org/10.5061/dryad.jq2bvq8q6)

## Description of the data and file structure

These datasets contain the data for analyses examining how nutrient release among songbirds varies by body mass, trophic position (as indicated by δ15N), and season (fall vs. spring). Data collection took place in September 2021 (fall) and May 2022 (spring) at the Braddock Bay Bird Observatory for a total of 151 songbirds from 31 species, 18 genera, and 11 families. Each bird was banded following normal banding operations by the Braddock Bay Bird Observatory. Datasets contain data on each bird’s sex, age, weight, tarsus length, wing chord, and other notes. Each bird’s subcutaneous fat load was qualitatively scored using a standardized scoring system ranging from 0 (no visible fat) to 5 (fat overflowing and greatly distended). Collected waste samples were freeze-dried and homogenized before e...,