I don’t know about you but I find that the whistling sound that pigeons make when they take off to be irritating because I feed squirrels and squirrels chuck their food onto the ground. Pigeons come along and eat this food. And pigeons are very nervous creatures. They are smart birds too. But because they are particularly cautious, they take off a lot and perch on a high place before returning to the food even if there’s the slightest possibility of an attack by a predator. So, I hear this whistling sound all the time which is annoying. In fact, it is annoying enough to me to stop feeding the squirrels or any other bird because I want a bit of peace and quiet. And also, I am concerned about my neighbours becoming upset.
Because of that I wanted to find out why pigeons make this whistling, trilling sound for the first few seconds when they take off. A study has the definitive answer. A team at the Australian National University studied this issue (“Sounds of Modified Flight Feathers Reliably Signal Danger in a Pigeon” – Current Biology). It is something which I don’t like to hear about but they trimmed one of their flight feathers on both wings, a different one each time to see whether it had an effect on the noise emitted. Not good that.
Trevor Murray, the lead author in the research, said:
“Then, as we’d released them, we recorded the sound produced. That way we could compare the sounds after the different treatments”.
And they concluded that the whistling sound that pigeons make is produced by special feathers on each wing. These are narrower than the other feathers and they vibrate due to “aeroelastic flutter”. Hummingbirds and manakin species, e.g., the South American club-winged manakin – Machaeropterus deliciosus, also use wings that make noise. This bird vibrates its wings together more than 100 times each second to produce a violin-like sound.
But why should pigeons make a noise when they take off? Apparently, they decided it was because they want to create an alarm call to the others in a group so when the other pigeons hear the sound they take off to. And this is the problem; I hear a bunch of pigeons all making the same sound together. If that happens regularly with 15 minutes intervals you really have to stop feeding. Pigeons are the authors of their own problems it seems to me. And the failure here is that pigeons make the noise when they are taking off to go somewhere else i.e. when there is no need to provide an alarm. They don’t make the sound if the glide off from a building.
On a separate topic, when pigeons are feeding in a group, a dominant pigeon will sometimes bully the others by pecking their heads with their beaks. Recently, one of these bullies spent all his time pushing other pigeons about who were trying to feed on plenty of food for all of them. The bully could have enjoyed the food with the others but he preferred to spend his time and energy kicking arse which seems unintelligent to me.
To return to the study, the researchers found that the particular feather that made this noise is “the third feather from the front on each wing”. I don’t know what that means to be perfectly honest. However, fortunately for me, the study provides a picture of the particular further concerned which you can see below.
When they removed the fourth feather from the front the pigeons made a noise but at a lower frequency compared to the fully intact pigeons. They thought that the fourth feather might modify the airflow over the third feather.
So, pigeons communicate with each other all the time without using their voice. Dr. Murray said:
“Even if you don’t have a very loud voice — these crested pigeons are very soft-spoken birds — you can still make sound in other ways to let your friends know they’re in trouble.”
Prof Kaplan said that this study adds to a large body of work on birds which show us that they are sophisticated creatures. People sometimes use the derogatory phrase “bird brain” to mean someone is stupid. But it should be used as a compliment because birds are pretty smart.