Zebra Finches Use Their Brains and Specialized Song System to Communicate Socially

Songbirds are known for their complicated calls that can either be learned or are innate. Now, scientists have taken a closer look at zebra finches and have found that the song control system in the brain is active during simple communication calls, revealing a bit more about the relationship between unlearned calls and an area of the brain responsible for learned vocalizations.

Almost half of all bird species in the world are songbirds. They can learn complicated vocal patterns which are described generally as song. These vocalizations mainly exist to select a partner or defend a temperature, and in the temperate zones of the Northern Hemisphere, it's often that only male birds song.

Yet all birds have calls that are innate-that is, they don't have to be learned and are used for communications purposes. In this particular study, scientists wanted to more closely look at the difference between learned songs and innate calls.

The scientists developed ultra-light microphone transmitters which they attached with rubber bands to the backs of zebra finch couples. They also attached a wireless recording system to male zebra finches to measure brain activity.

What did they find? Not every call produced an answer in a zebra finch's partner. In fact, they found that a call from a partner only qualifies as an answer if it is made within two seconds. With this in mind, they created a matrix that clearly showed that two partners exchange calls with one another, which underlies an important social component.

What was more interesting was what was happening in the brains of these birds. They found a clear correlation between an area that's important for the production of song, known as nucleus RA, and the occurrence of a "stack" call, which was what was used for social communication.

"This connection between an innate call and the activity of a brain area important to learned vocalizations suggests that during the evolution of songbirds, the role of the song area in the brain changed from being a simple vocalization system for innate calls to a specialized neural network for learned songs," said Manfred Gahr, coordinator of the new study, in a news release.

The findings are published in the journal PLOS One.