Ocyphaps
By flapping its wings rapidly during its flight in case of danger, the Australian pigeon emits a noise that alerts other birds.
hen a bird takes off in case of danger, its congeners generally take off after it. Some species give an alarm call, but this is not always the case. Could the movement or the sound of the flight be the signal? According to Trevor Murray of the University of Australia, Canberra, and colleagues, a characteristic wing noise can be interpreted as a signal of danger, at least in the case of the longup pigeon (Ocyphaps lophotes), an Australian pigeon .
The researchers showed that the eighth primary feather of this pigeon emits two sounds, one at a frequency of 1.3 kilohertz when the wings rise and the other at 2.9 kilohertz when the wings descend. This alternation of notes is repeated at the speed of wing beats. The researchers recorded this sequence and played it to pigeons by modulating the speed. If the sound is played normally, the birds fly away; if it is slowed down (as if the bird was flying away in the absence of danger), the birds do not flee.
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