Birds can control their wings independently

How can little birds sing so loud?

But how is that supposed to work? Take the wren, the prime example of a tiny bird with an extremely loud call. It measures just ten centimeters, weighs around ten grams and sings at a volume of up to 90 decibels - as loud as a truck that drives by! If the amount of air makes the volume, how can such a small animal produce so much air?

Stefan Bosch: “There are a few things that come together: If you have a smaller windpipe, like the wren, you have to build up more pressure to be able to force a lot of air through. Birds can do this because they not only have their lungs, but also additional air sacs that are mainly distributed in the abdomen and chest. There are also small air sacs in various more or less large bones, from shoulder, pelvic and vertebral bones to tubular bones of the wings. These fill the birds by inhaling like a bagpipe and then push them empty again with muscle power. The air flows with great pressure through the syrinx, the lower larynx, and creates the tones. "

This means that birds can sing and breathe independently of each other: The air for singing does not have to be inhaled immediately beforehand, but can be stored in the air sacs, so to speak. Now these air sacs, which enable our wren to sing so loudly with high pressure, will not be particularly large. Will it probably have to refill very soon?

“Yes, nature has a solution for that too,” says Stefan Bosch. “Birds can take micro-breaths while singing, that is, they can breathe in at lightning speed and unnoticed. So they fill up the air sacs at the same time. "

And the bird world has another special feature in store that enables loud singing. To do this, one has to understand what the syrinx looks like, the lower larynx that is responsible for making sounds: it is where the trachea splits into the two main bronchi, which then lead into the two lungs. At this fork, membranes are made to vibrate by the flow of air, similar to our vocal cords. This is how the tones are created. The syrinx is much wider than, for example, our glottis. The bird can also control the diameter with the help of muscles and thus the volume of its song. If the Syrinx is normally expanded, it offers little resistance to the air flow. This also allows a large amount of air to flow through, which ensures the volume of the singing in front of our bedroom window.