A pigeon springs from the lawn and a high, wavering whistle follows it into the air. With a Crested Pigeon, that sound comes from the wings. The upright crest on its head is a useful identification feature, but it is not the whistle-maker.
The interesting part is that the noise can also tell other pigeons something about the departure. A hurried escape sounds different from an ordinary flight.
A flight feather makes the sound
Researchers at the Australian National University investigated an unusually narrow primary flight feather, the eighth primary, usually shortened to P8. High-speed video and recordings linked the high note to this feather during the downstroke. The bird’s wing therefore supplies both the movement through the air and a repeating sound.
Think of the distinction between a bird’s voice and its other noises. A coo comes from the vocal system. Here, a specialised feather is part of a mechanical sound-producing system. Calling every bird noise a call can hide that difference.
The study did more than notice an association. Researchers examined flights with particular feathers removed and tested how other pigeons responded to recordings. The published study summary reports that P8 was necessary for the alarm response to recordings of escape flight. Feather structure mattered to what the listeners heard.
Faster escape changes the message
In a rapid escape, faster wingbeats make the whistle repeat more quickly. That relationship helps explain how a sound tied to flight can carry information about urgency: the movement involved in fleeing also changes the sound.
ANU’s account describes other pigeons responding to the faster alarm sound. This is stronger evidence than seeing a flock take off together, because a shared sight of danger could also explain a group departure. Playback lets researchers test the sound itself.
It does not follow that every whistling take-off means a predator is present. Wings can whistle during ordinary departures too. The distinction concerns the pattern associated with escape, rather than a simple rule that whistle equals emergency. Nor should a person infer the precise cause of a bird’s movement from one sound.
Crested Pigeon or Topknot Pigeon?
Look at the whole bird and its surroundings. BirdLife describes the Crested Pigeon as a native pigeon with a slender, pointed black crest. It often feeds on the ground in open country, including farms, parks and gardens. Its diet is mainly seeds, and it needs access to water.
The Topknot Pigeon is a different native species. Its larger, swept-looking head decoration is not the thin spike of a Crested Pigeon. It is associated with rainforest and fruiting trees, where birds feed above the ground. A pigeon with a head ornament is therefore not automatically a Topknot Pigeon, even when that common name seems to fit.
These are useful comparisons, not substitutes for checking a clear view against a regional field guide. Sound alone may be hard to assign when several birds leave at once.
Listen without making the bird flee
The best opportunity is an ordinary departure that happens while you are already watching from a distance. Note the crest, whether the bird was feeding on the ground, and the sound as it takes flight. A quiet observation can reveal more than pursuing it for a recording.
Do not chase pigeons or play alarm recordings to demonstrate the effect. If your approach makes a resting or feeding bird leave, give the next one more room. Understanding an alarm signal should help us recognise disturbance, rather than create it.