Einstein is an African Grey parrot who can imitate a spaceship, a laser, and a chimp at will, besides uttering sage words of wisdom upon receiving a cue (and a peanut) from her trainer, Stephanie White. Einstein has a working vocabulary of over 200 words, an impressive number, but nowhere near the upper limit of the range of language that birds have been shown to learn and use.
Three classes of birds – parrots, songbirds and hummingbirds have been shown to have the ability to mimic human speech. Since birds lack vocal cords, the sounds we hear are produced by vibrations of their throat muscles and membranes – you could call it a form of whistling. Vocal mimicry requires significant learning and cognitive capacities in these birds, and involves advanced and specialized brain regions. So, why do they do it?
To answer this, we need to look at the one thing that the bird species that have learned to mimic human speech have in common – they are all highly social birds. In the wild, these birds live in large flocks that inhabit well-defined territories. Within their flocks, vocalizations contribute to the all-important process of communication – warning against predators, wooing mates, communicating about food, and simple socializing. Mimicry serves an important function in this regard – bird songs within flocks grow to resemble one another, and form local ‘dialects’ that can be distinguished from other ‘dialects’ in neighboring territories. Mimicry establishes important patterns of vocal learning, enabling these birds to adapt their songs to their flocks and communicate more effectively.
When these birds are domesticated, they bring their friendly natures into the mix, and try to socialize with their new ‘flocks’ – their humans. And since the humans prove to be remarkably less adept when it comes to learning the vocalizations of their new pets, these birds put the skills that they evolved in the wild into good use and successfully learn to mimic the ‘calls’ that they hear. Whether the bird wants some attention, or just wishes to chat up its new flock, mimicry of their owner’s voice serves the purpose.
As mentioned earlier, parrots are not the only group of birds that can mimic human speech, although they are definitely the industry leaders – a former world record holder is a budgerigar (a small, long-tailed parrot) called Puck, with a vocabulary of 1728 words. Several songbirds, corvids(crows and ravens), hummingbirds, and some mammals including cetaceans (dolphins and whales) and even elephants have been shown to have limited capacity for mimicking human speech. What gives parrots their decided advantage over all these other species ? A recent study by researchers at Duke University claims to have solved this problem by doing a comparative study of the brains of several different species of parrots, hummingbirds and songbirds. Parrots were shown to have specialized ‘core’ and ‘shell’ regions in their brains that were activated during vocalization, while songbirds and hummingbirds only had the ‘core’ region. The relatively larger and amorphous ‘shell’ region may have contributed to the superior vocal learning capacities of these birds, according to the authors.
Do birds understand the words that they say? There is significant controversy in the field regarding this. Many researchers believe that the birds simply use the words they learn to respond to different contexts, like regular animal ‘call’s, and do not associate any intrinsic value or meaning to the words themselves. Others believe that the cognitive ability of these birds extend to learning the meanings of words and associating them to objects or even abstract concepts like zero. Any discussion in this regard would be incomplete without mentioning Irene Pepperberg and her studies over more than 30 years on the African grey parrot Alex. Alex, who had an extensive vocabulary, and could correctly identify objects by their color and number and use words like ‘same’, ‘different’, ‘bigger’ or ‘smaller’ in their correct contexts.
To conclude, birds mimic human speech as a form of social behavior, adapting the vocal learning methods they learned in the wild to fit in with their new ‘flock’, i.e. their human owners. Whether or not they have any ability to comprehend the meaning behind the words remains, at present, controversial.