Urban Birds Dull in Color Due to Pollution and Heavy Metals, Study Finds

City-dwelling birds are getting duller, according to a study that found urban species are darker and less colorful than those in rural areas.

Urban Birds Dull in Color

A study published in the journal Landscape and Planning examined 547 bird species in China and found that those living in cities had duller and darker plumage compared to their rural counterparts. This conclusion was supported by an analysis of 59 studies published in March in Biological Reviews, which also noted that urban birds had less vibrant feathers, particularly in yellow, orange, and red hues. 

City birds tend to be covered in grime, but even if they were cleaned, their brightness would likely still pale in comparison to rural birds. This is attributed to the negative impact of pollution, specifically heavy metals, on the melanin pigment responsible for black, brown, and gray feathers.

Effects of Pollution

Research shows that melanin can bind to heavy metals like lead, suggesting that duller and darker birds may be storing these toxic chemicals in their plumage. As Kevin McGraw, a biologist at Arizona State University, notes, accumulating more melanin could provide a survival advantage by sequestering harmful compounds in feathers.

The findings of the study reveal a concerning trend in urban bird populations, highlighting the impact of pollution on their physical appearance. Efforts to reduce environmental pollutants could help restore the vibrant plumage of city-dwelling birds, promoting their wellbeing and survival in urban habitats.