Parrots are masters of mimicry who are able to repeat hundreds of unique sounds, including human phrases flawlessly. Everyone knows that a parrot is able to do this, but do we have any idea why they possess this ability?
A recent study conducted by a team of researchers from Duke University came up with the conclusion that this ability all comes down to the bird’s brain structure. However, parrots’ particular brain structure had gone unnoticed in the last 34 years of research that has been published. These more recent findings may also offer some new information into the neural mechanism of human speech.
What exactly does their brain contain that makes them such great vocal imitators?
By examining parrot gene expression, the new study found that parrot brains are structured differently than the brains of songbirds and hummingbirds (which also exhibit vocal learning).
A bird’s brain has defined centers, known as ‘cores’, which control vocal learning. This is what most types of birds possess, but parrots have an additional structure that scientists call ‘shells’ or outer rings. The neurons in these shells, which surround the established vocal centers of the parrots’ brains, play an essential role in vocal learning and other complex motor behaviors.
The group of scientists found that the shells are relatively larger in species of parrots that are well known for their ability to imitate human speech. Before this, the budgerigar (common pet parakeet) was the only species of parrot whose brain had been tested for these mechanisms of vocal learning.
This team included researchers from Denmark and the Netherlands who donated precious brain tissue for the study. They characterized the brains of eight parrot species besides the budgerigar, including conures, cockatiels, lovebirds, two species of Amazon parrots, a blue and gold macaw, a kea and an African Grey parrot.
The researchers were looking for very specific gene markers that were the cause of specialized activity in humans and song-loving birds. They compared the gene expression of all these species with that of the common pet parakeet, and found that even the most ancient species (the kea of New Zealand) in their study had a shell structure. This suggests that neurons in the shells of parrot species’ brains were developed about 29 million years ago.
The study is still incomplete, as researchers are yet to determine how they are able to reproduce the same sets of words so perfectly. Much remains to be discovered. For now, however, we’ll have to be content with the sound of our own voice.