Urban Great Tits have paler plumage compared to their countryside-dwelling counterparts, according to new research.
The study, published in Journal of Animal Ecology, explains how, as the yellow pigment of the breast feathers of Great Tits comes from the food they eat, the paler yellow plumage of urban birds indicates that the urban environment affects the entire food chain.
Previous research has shown that animals in cities are "duller" in terms of yellow-orange-red colour tones compared to their non-urban counterparts, while another study found that urban Great Tits are less stressed than those in woodlands.
Great Tits in cities are duller than those in the countryside, according to a new study (Martin Webb).
"We used feather samples collected from Great Tits in cities and forests across Europe. Different methods all confirmed that urban Great Tits are paler," said Hannah Watson, biology researcher at Lund University, and one of the authors behind the study.
"Our findings suggest that birds in the city are not getting the right diet. This can help us understand how to create urban environments that are more beneficial for biodiversity. By planting more native trees and plants in our gardens and parks we can help small birds, such as Great Tits, by providing them with a healthy diet of insects and spiders for themselves and their chicks."
The yellow colour in the Great Tit's feathers comes from carotenoids, which the birds get from the insects they eat. These insects, in turn, obtain the nutrient from the plants they feed on. Carotenoids are important antioxidants that help the body combat the toxic effects of pollution. If Great Tits in cities cannot obtain enough carotenoids from their food, their plumage becomes paler, resulting in weaker defences against the adverse health effects of pollution.
Surprisingly, the researchers found that the effects of cities on birds vary across Europe. For example, in Lisbon, forest-dwelling Great Tits displayed much brighter feathers than city-living birds. In Malmö, on the other hand, the difference in plumage between city and forest Great Tits was considerably less noticeable.
Reference
Capilla-Lasheras, P, Isaksson, C, López‐Idiáquez, D, Pérez‐Tris, J, Salmón, P, & Watson, H. 2023. Urbanisation impacts plumage colouration in a songbird across Europe: Evidence from a correlational, experimental and meta‐analytical approach. Journal of Animal Ecology. DOI: https://doi.org/10.1111/1365-2656.13982
