# Bird Community Colours Across Different Types of Habitat

## TL;DR

This study explores how bird community colors vary across different habitats in Italy, revealing patterns linked to environmental factors and species relationships.

## Contribution

The study provides new insights into how bird community coloration is influenced by habitat types and landscape heterogeneity.

## Key findings

- Grey, white, black, and brown are the most common colors in bird communities.
- Color diversity increases with species and land use richness but decreases with higher edge density.
- Closely related species in the same habitat show greater color diversity for better recognition.

## Abstract

Bird colouration influences interactions with the environment and between species. However, studies focusing on the colouration of bird communities are scarce. This research utilized a large dataset to examine the relationship between community colours and different habitats in Italy. The dominant colours were found to be grey, white, black, and brown. Black was less common in closed habitats like forests, brown was prevalent in forests and shrublands, and white was more common in wetlands, water bodies, and urban areas. Yellow was generally rare but slightly more frequent in deciduous forests. Increased landscape heterogeneity led to a rise in brown, green, rufous, and yellow percentages but decreased melanins and structural colours. The overall colour inequality of bird communities decreased when increasing the number of species and land use richness, while it increased with higher edge density. Notably, communities with closely related species in the same habitat showed greater colour diversity, suggesting that they evolve distinct features for better species recognition.

(1) The bird colouration is the result of adaptation to environmental conditions, predator–prey relationships, and sexual selection (intraspecific competition and signalling of quality). Only a few studies have explicitly explored the plumage colouration of birds at the level of species communities. (2) Methods: We combined data with bird plumage colours and their spatial distribution at a large spatial scale in Italy, exploring the relationship between community colours and different types of habitats and landscape heterogeneity. (3) Results: Overall, we found that the more representative colours of avian communities were grey, white, black, and brown. The percentage of black colour in the community was smaller in close habitats (e.g., forests). A high percentage of brown was observed in forests and shrublands, whereas a high percentage of white was found in wetlands, water bodies, and urban areas. The percentage of yellow was relatively low overall, but it was slightly higher in deciduous forests. Land use richness increased the percentage of brown, green, rufous, and yellow, while negatively affecting other pigments (black and grey = melanins, purple = structural, and red = carotenes). The community colour inequality decreased when the species and land use richness increased, while it increased when the weighted edge density of surrounding landscapes increased. Finally, we found that bird communities that are made up of closely related species show a wider variety of colours (e.g., lower colour inequality). This supports the idea that closely related species that live together develop different features to improve species recognition. (4) Conclusions: We found that the colours of bird communities are related to the type of environment.