Darwin Proved Right – Again!
It was none other than Charles Darwin who first suggested that birds use their wings to communicate as well to fly. 150 years later, scientific research appears to have proved him right.
Darwin was fascinated by avian communication. In "The Descent of Man and Selection in Relation to Sex" he described both the sounds that emerge from birds’ beaks and the more percussive noises that they make with other parts of their bodies including their feet and feathers. He suggested that both types of sound were important for communicating with other birds.
Since Darwin’s death, much time and money has been devoted to studying birds’ songs and shrieks but not the sounds they make with their wings.
New Research into Avian Communication
However, a recent study of crested pigeons found that the birds use one of their main flight feathers to produce a warning sound for the benefit of their companions when they are flying away from danger. We now know why pigeons can make such a terrible noise taking off!
The Evolution of Birds
Prior to the most recent research, it wasn’t known whether that noise was just a side-effect of flight. But a single feather has been identified as being responsible for causing the sound and it is only deployed when the birds sense danger. This suggests that evolution has led to the development of the ability to emit warning sounds.
The majority of research which has been conducted into avian communication has focussed on vocal sounds. This new discovery proves that the situation is far more complex and that Darwin was right.
Australian National University
The study was conducted by experts at The Australian National University. High speed video was used to confirm that the feathers were being employed to make a whistling sound. Feather removal was also conducted. It was found that the birds’ unusually narrow eighth primary wing feather produces a distinctive note when the wings are flapped. The birds flap their wings harder when fleeing danger and the tempo of the sound changes.
Replaying the Sounds
The researchers recorded the flight sounds and played them to other pigeons. Birds were much more likely to flee when they heard the flight of a bird with an intact eighth primary feather. When the sound of a pigeon with that eighth feather removed was played, the other birds just looked around instead of taking off.
Darwin was a pigeon fancier himself and would have been delighted to hear that his theory has been proved via research into these birds.