A team of Australian biologists has discovered that the bronze crested pigeon ( Ocyphaps lophotes ) emits a special sound with its wings that alerts its companions that a predator is nearby .
Specifically, the sound is equivalent to a kind of whistle emitted without opening the beak . Although for the human ear this whistle is very similar to that emitted by birds when taking off from the ground, pigeons perfectly distinguish when it is an alarm signal. Acoustically analyzing the sound, Robert Magrath and Mae Hingee of the Australian National University have identified that this "secret alarm" is louder and has a specific tempo that pigeons quickly identify. Details of the research are published in Proceedings of the Royal Society B.
