Why is it that the feathered friend who shares your home not only has his/her repertoire of instinctual screeches, chirps and whistles but can also mimic some of your words, phrases or even beeping appliances but the birds outside your window stick to their chirps? A recent study led by Duke University researchers and supported by an international team of scientists set out to find out why certain bird species are better at imitating sounds than other birds.
Until recently, the brain of the budgerigar had been looked at in regard to mechanisms of vocal learning. The new study examined the brains of eight additional parrot species: cockatiels, conures, lovebirds, two species of Amazon parrot, an African grey parrot, blue-and gold-macaw and a kea. Researchers set out to find specific gene markers that are associated with specialized activity in the brains of people as well as song-learning birds. Results showed that parrot brains have unique structural differences from those of songbirds and hummingbirds, which are also vocal learners.
Parrots have what researchers call “cores” (distinct centers in the brain that control vocal learning), and they have outer rings that are associated with vocal learning as well.
In their findings, which were published in the scientific journal PLOS ONE, researchers report that the parrot brain “uniquely contains a song system within a song system.” The parrot “core” song system is similar to the song systems of songbirds and hummingbirds, but the “shell” song system is unique to parrots. Moreover, researchers found that these shells are relatively bigger in species of parrots that are well known for their ability to imitate human speech.
The kea, which is native to New Zealand, was included in the study because it represents the most ancient parrot species. Researchers found that the kea has a rudimentary shell structure, which suggests that the populations of neurons in the shells likely arose some 29 million years ago.
“This finding opens up a huge avenue of research in parrots, in trying to understand how parrots are processing the information necessary to copy novel sounds and what are the mechanisms that underlie imitation of human speech sounds,” said Mukta Chakraborty, a post-doctoral researcher in the lab of Erich Jarvis, an associate professor of neurobiology at Duke and a Howard Hughes Medical Institute Investigator.
Click here to read the study published in Plos One.