Successful urban birds sport different colours from unsuccessful ones Premium

Global study reveals colorful urban birds thrive, challenging long-held assumptions in urban ecology, with implications for biodiversity conservation.

In 2016, when Juan Diego Ibáñez-Álamo at the University of Granada in Spain met Kaspar Delhey, an expert in bird coloration at the Max Planck Institute for Biological Intelligence, a new collaboration was born.

“He suggested we study whether urbanisation is associated with differences in bird coloration,” Delhey said.

Many studies have investigated how urban noise has been changing the way city birds talk to each other. But scientists know little about what urbanisation is doing to the way birds look.

The collaboration soon blossomed into the world’s first large-scale, global study of how urban environments can control which birds — and which colours — can thrive in cities.

In a new study, Delhey, Ibáñez-Álamo, and their colleagues reported what they found when they analysed colour data from nearly all bird species around the world alongside a reference database.

The results were unexpected.

“Contrary to expectations, bird species that do well in cities tend to be quite colourful,” Delhey said. “Some of the least successful species were largely brown, colours that we humans often consider dull or cryptic.”