When I got your question, I called up my friend Jessica Tir, a graduate student at Washington State University who studies songbirds.
She said one of the main reasons a bird will make a loud sound is to attract a mate. When the birds find each other, they can make a nest for their eggs and wait for babies to hatch.
“That’s the song they are going to sing for the rest of their life,” Tir said.
In the lab at WSU, Tir records songbirds’ songs on microphones to learn more about how they communicate with each other, especially when they are hungry. The research will help us learn more about communication and how much food there is some birds’ habitat.
While humans can make sounds with help from their vocal cords, birds use a part called the syrinx (SEE-RINKS). Ostriches have a much bigger syrinx than, say, a tiny swallow, but they work in similar ways.