Are Ultraviolet Signals a Special Channel in Avian Communication?
It is widely known that birds are sensitive to ultraviolet (UV) light, and that they use UV reflecting signals in choosing mates. This led to the proposal that UV signals in birds may represent private channels of communication hidden from predators, because most mammalian predators of birds are unlikely to see UV light. This idea has held great sway with researchers and the public, sustained no doubt by human fascination with an area of communication invisible to us. However, the primary predators of songbirds are often birds of prey that can see UV light, shedding doubt on the idea that UV reflecting patterns represent “special” signals. A range of recent studies, including mate-choice experiments, models of visual processing, and comparative analyses, have claimed to provide support for and against the theory that UV signals are special. We summarize the evidence for and against this idea and conclude that, while further work is required, current evidence generally does not favor th
