Trophic discrimination of amino acid-specific nitrogen stable isotopes in raptor nestlings: implications for estimating trophic position

Bulk stable isotope analysis of carbon and nitrogen is commonly used to assess trophic relationships among organisms in a wide variety of ecosystems. However, compound-specific stable isotope analysis of individual amino acids may be a more accurate approach for resolving food web structure. We compared the applicability of bulk and compound specific methods in an Arctic tundra ecosystem. Specifically, we determined bulk δ13C and δ15N, as well as amino acid specific δ15N, in red blood cells from nestling raptors and muscle samples from common prey species. We subsequently estimated bulk and amino-acid specific trophic discrimination factors (TDFs) for nitrogen in gyrfalcons (Falco rusticolus) using high-precision diet estimates from nest cameras to compare against TDFs in the literature. Although bulk δ15N values of secondary consumers were enriched relative to primary consumers, overlap occurred across groups and greater separation was apparent using δ15N of amino acids. Comparing red ..., , , ## Trophic discrimination of amino acid-specific nitrogen stable isotopes in raptor nestlings: implications for estimating trophic position

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

## Description of the data and file structure

These datasets include both bulk and compound-specific stable isotope values from a variety of species collected in the Seward Peninsula in Alaska in .csv format.

### Files and variables

For the following CSV's, there are quite a few repeated variables and as such they are only defined in the data sheet they first appear in. Furthermore, some of the variable names are self-explanatory and as such are not defined. Finally, some column names were only used for record-keeping purposes and are not relevant to analysis. These column names are thus omitted to avoid confusion.

**File: CSIA_Bulk.csv**

**Description:** Dataset for compiled bulk and compound specific stable isotope values across all species. 

** Missing valu...,