All of us are well aware that many animals instinctively sound an alarm to alert other members of some impending danger. Latest research has shown that crested pigeons do this in a surprisingly non-vocal way. This is achieved as one of their main flight feathers produces a critical high-pitched sound as the birds fly away. As they flap faster to escape a predator, that alarm signal automatically increases in tempo.
150 years ago, Charles Darwin proposed the idea of non-vocal "instruments" in birds. However, this idea has been a difficult one to test. Scientists had long known that crested pigeons make loud sounds when they fly and that is why they are known as the "whistle-winged pigeons." To confirm that the whistling feathers were indeed an alarm signal, researchers conducted feather-removal experiments and recorded the results in high-speed videos. These studies showed that the birds' unusually narrow eighth primary wing feather produces a distinct note with each down stroke. The birds while fleeing danger produce wing sounds that have a higher tempo.
When the researchers played flight sounds to other pigeons, individuals were much more likely to flee upon hearing the flight of a bird with an intact eighth primary feather. On playing the sound of a pigeon with that eighth feather removed, they often just looked around instead of taking off. For long, ornithology has been a neglected branch of botany. This new finding symbolizes a new era in this field and may have possible repercussions in the field of bio technology as well. For once we start paying attention to the complex instrumental sounds; the future has a lot to unleash.