Darwin Was Right: Birds Really Are More Colorful In The Tropics
The long-held idea that birds living in the tropics are more colorful than those living closer to the poles is true, suggests a recent study
A recently published study has confirmed an old and widely accepted idea that songbirds living in the tropics are more colorful than their counterparts who live closer to the poles. This idea was independently proposed by English naturalists, Charles Darwin and Alfred Russel Wallace, and by German geographer, Alexander von Humboldt (read more about him here). These three remarkable scientists traveled separately to different destinations throughout the tropics during the early- to mid-1800s, and were all completely enthralled by the vibrant colors they observed there, especially those displayed by birds.
The conjecture that tropical birds are more colorful is an attractive idea but has remained scientifically untested until recently because such a study requires vast amounts of geographic data as well as access to cutting-edge image processing technologies and computer power — and access to thousands of bird species, of course.
Color and colorfulness
But recently, an international team of scientists based at the University of Sheffield, with some team members also at the Natural History Museum at Tring, the University of Pannonia, the University of Bath, and the University of Debrecen, collaborated to test the hypothesis that songbirds are more colorful in the tropics.
Comprising almost 60% of the roughly 10,000 known species of birds alive today, songbirds include such familiar feathered friends as sparrows, finches and crows, and are taxonomically classified as passerines (‘perching birds’), based on the arrangement of their toes that evolved for perching.
To do this research, the scientists photographed more than 24,000 passerine museum specimens from more than 4,500 songbird species that are curated in natural history museum collections around the world. Most of the specimens used in this…