Colorful birds face heightened extinction risk around the world

Many of the functional traits that mediate extinction risk across the tree life relate indirectly to a species’ ability to persist in a changing world. Yet, there are certain traits such as coloration that directly affect human interactions with wildlife. Here, we use an existing dataset of color metrics for 4334 passerine bird species combined with global functional trait data to determine whether two measures of extinction risk covary with the colorfulness i.e., number of color loci for each species. We also control for the potentially confounding effects of three other traits related to a species’ size, dispersal ability, and forest dependency. Finally, we assess whether the global relationship between extinction risk and colorfulness varies by 1) biogeographic realm or 2) breeding latitude and human development index. Overall, we find that more colorful passerines are at a greater risk of extinction than more drab species, and this is especially true in Indomalaya and Australasia. We also find that the strength of this relationship is greater at higher breeding latitudes but also in countries with lower human development index. More colorful birds are likely at greater risk of extinction due to the trade in pet birds that favors more attractive species. In stark contrast, there is also a potential bias resulting from the increased public, research, and conservation focus on more charismatic species. More colorful birds should be used as successful conservation emblems if we are to avoid eroding the world’s colorfulness.