Taking a Bird's-Eye View…in the UV: Recent studies reveal a surprising new picture of how birds see the world

Extract

People have long delighted in the vibrant colors of birds. Charles Darwin, for one, wrote extensively on their “beautiful plumes” and “brilliant tints.” Indeed, the varied and attractive coloration of birds—and the obvious importance of vision in their biology—has made them favored organisms for biologists studying visual communication. Avian research has played key roles in the study of visual signaling and in the burgeoning field of sexual selection. Biologists studying sexual selection have documented for one bird species after another whether females choose brighter-feathered males, whether plumage luster correlates with health, whether highly ornamented individuals win in male–male encounters, and whether particular colors and patterns have specific functions.

But do we really know how beautiful and brilliant bird coloration can be? In recent years, some researchers have found evidence that we don't. A bird, it turns out, may be more colorful to another bird than to the human eye. For unlike humans, birds can perceive wavelengths in the ultraviolet as well as the visible range of the spectrum. So a bird is able to see ultraviolet “colors” in another bird's plumage that humans cannot.