Adaptive and non-adaptive convergent evolution in feather reflectance of Channel Islands songbirds

Convergent evolution is widely regarded as a signature of adaptation. But testing the adaptive consequences of convergent phenotypes is challenging, making it difficult to exclude non-adaptive explanations for convergence. Here, we combined feather reflectance spectra and phenotypic trajectory analyses with visual and thermoregulatory modeling to test the adaptive significance of dark plumage in songbirds of the California Channel Islands. By evolving dark dorsal plumage, island birds are generally less conspicuous to visual-hunting raptors in the island environment than mainland birds. Dark dorsal plumage also reduces the energetic demands associated with maintaining homeothermy in the cool island climate. We also found an unexpected pattern of convergence, wherein the most divergent island populations evolved greater reflectance of near-infrared radiation. However, our heat flux models indicate that elevated near-infrared reflectance is not adaptive. Analysis of feather microstructure..., , , # Adaptive and non-adaptive convergent evolution in feather reflectance of Channel Islands songbirds

[https://doi.org/10.5061/dryad.qrfj6q5nk](https://doi.org/10.5061/dryad.qrfj6q5nk)

This dataset contains museum specimen information, raw dorsal and ventral feather reflectance values, heat flux simulation outputs, and visual modeling outputs.

## Description of the data and file structure

*bird_database_linked_dryad.csv*:

* **arctos_id** = specimen ID in arctos database
* **genus** = abbrevation of genus + species name
* **arctos_name** = scientific name in arctos database
* **mvz_name** = name of specimen in MVZ database
* **mvz_specimen_id** = specimen ID in MVZ database
* **common_name** = common name of species
* **original_file_id_name** = abbreviated genus + species name
* **file_id_name** = abbreviated genus + species name
* **spp** = abbreviated genus + species name
* **file_file_numbers** = unique numbers associated with files from each specimen
* **file_ID** = ID given to ...