Coevolution and the diversification of nestling ornamentation in a species-rich avian radiation

Conspicuous juvenile phenotypes are puzzling to evolutionary biologists. Why should organisms vulnerable to predation boldly broadcast their presence? We reconstructed the evolutionary history of nestling phenotypes across the estrildid finches (family Estrildidae) a radiation exhibiting unparalleled diversity in nestling ornamentation. Many are parasitised by Vidua finches whose offspring mimic host nestling phenotypes. We examined the role of brood parasitism, predation, sibling competition and signalling environment in the diversification of nestling ornamentation. We found that parasitised lineages exhibit elevated rates of nestling ornamentation evolution compared to unparasitised ones. Despite this, the extent to which nestlings were ornamented did not differ between parasitised and unparasitised lineages, contrasting with systems where coevolution proceeds at the egg stage and generates increased complexity in host traits. Species occupying denser habitats had increased ornamenta..., Scoring estrildid nestling characters
We sourced photographs of the nestlings of as many estrildid finch species as possible and used them to score nestling appearance. Photos were sourced from G. Jelmer Huisman’s “Estrildid Finches of the World” (Huisman, 2021), Robert Payne’s monograph on estrildid mouth markings (Payne, 2005), Gerhard Hofmann’s online gallery of estrildid nestling mouth markings (www.hofmann-photography.de/index/02_estrild/index_estrild/mouthmark/) and Jamie et al.’s (2020) study on nestling estrildid finches from fieldwork in Zambia. These photos include birds reared both in captivity and the wild. Intraspecific variation in nestling appearance is extremely low in estrildid finch species (Jamie et al., 2020)and there is no evidence to suggest that birds reared in captivity have mouth markings that differ from those in the wild. Of the 138 species of estrildid finches, nestlings have been described for 109 species and we were able to source photos of 96 species.
To s..., , # Coevolution and the diversification of nestling ornamentation in a species-rich avian radiation

[https://doi.org/10.5061/dryad.x95x69pvh](https://doi.org/10.5061/dryad.x95x69pvh)

## Description of the data and file structure

Ecological and mouth marking data for estrildid finch species. Used to test adaptive hypotheses about the evolution of nestling ornamentation across the family. EstrildidComparativeData.csv contains data for a subset of species with mouth marking data. EstrildidComparativeData_DiversificationAnalysis.csv contains data for all estrildid species included in phylogeny. Missing data given as NA.

### Files and variables

#### File: EstrildidComparativeData.csv

**Description:** 

##### Variables

* animal: List of species names based on current (2024) taxonomy with e.g. updated genus names.
* English_name: English name of species based on eBird/Clements (2024)
* Number_medial_palate_spots: Number of medial spots on upper palate
* Number_lateral_palate_spots: Number...,