Feather growth rate and hormone deposition vary with elevation but not reproductive costs in resident Mountain Chickadees

Many organisms engage in metabolic tradeoffs to manage costs associated with reproductive output which often leads to these costs carrying over into the future. Compensatory mechanisms vary across life history strategies and are expected to result in near optimal fitness gains for the investor.  Here we investigated whether environmental differences associated with increasing montane elevation and variation in reproductive output of a resident passerine songbird, the Mountain Chickadee (Poecile gambeli), were related to physiological condition during annual molt. Higher elevations are associated with harsher environmental conditions during the winter, which results in later and shorter breeding seasons than at lower elevations. We sampled the outermost tail feathers from adult birds in the fall after their prebasic molt, which initiates closely after reproduction (e.g., after parental care has ceased, ~1-3 weeks). We measured the hormone corticosterone deposited in feathers (fCORT) and ..., This dataset was collected in a long term field system in the Sagehen Experimental Forest (Sagehen Creek Field Station, University of California, Berkelely) in the Sierra Nevada, USA during 2018-2021. The majority of the data is observational and was collected during the reproductive season of the animals monitored in the study (Mountain Chickadees, Poecile gambeli). This raw data was entered into ongoing database files and was not otherwise filtered or processed. The other subset of the data was collected in a wetlab environment using a standard ELISA. Raw hormone quantity values calculated from a standard curve were collected and corrected for feather size (both mass and length) but otherwise left unprocessed. , , # Feather growth rate and hormone deposition vary with elevation but not reproductive costs in resident Mountain Chickadees

[https://doi.org/10.5061/dryad.4f4qrfjkz](https://doi.org/10.5061/dryad.4f4qrfjkz)

This dataset contains three main files. The first two are .CSV files that contain the raw data of the study and the data used in all the analyses. The 3rd file is a .R file that contains all of the analysis code, variable descriptions, and any minor data transformations.

1\. AdultFeather_data_030724.csv

2\. MOCH_BreedingMaster_030724.csv

3\. Adult_feather_analysis_083023.R

### File 1: Variable Descriptions for File 1: AdultFeather\_data\_030724.csv

* B_ID: individual identifier of sampled bird
* Year: the year in which a sample belongs
* Elevation: site location; H is for high elevation and L is for low elevation
* Breeder: whether the bird was recorded breeding; all NA's are individuals with sampled feathers
* Sex: male, female, or null (if sex unknown) designation
...