Tuesday, September 17, 2013

Why Do Birds Talk?

When a World Bird Sanctuary bird show concludes at Stone Zoo in North Boston, people often come up and ask us questions about the birds. 

Members of the corvid family are know for their ability to mimic human speech
One of the questions I am frequently asked is why parrots, like Nemo, our African Gray Parrot, talk.  Well…they can’t really talk, but have the ability to mimic sounds they hear.  To answer this, we must start a little earlier than the training process.  Actually many bird species such as corvids (crows, jays ravens), starlings, mynas, and lyrebirds have been observed mimicing human speech and also many other sounds, but many of the birds in our show, such as raptors and chickens, cannot learn to mimick. 

So why can't Clark, our Bald Eagle, talk?  Well, it turns out that not all birds are vocal learners and not all birds have the necessary degree of control of their syrinx for mimicry.   In fact, vocal learning has only been found in songbirds, parrots, and hummingbirds.  This means that these birds are not hatched knowing the same songs and sounds they make as adults, but pick them up from their environment, much as humans are not born knowing languages such as English or German.  Most birds learn these sounds from their parents or neighbors. 

Additionally, birds do not have vocal cords, but rather make sounds using their syrinx, which is located at the point where the trachea divides into two bronchial tubes.  There is great diversity in the structure of the syrinx, especially between orders of birds.  This difference allows for a varying degree of complexity and control over the sounds a bird can make.

Now that we know why some birds cannot talk, the next question is why would birds ever learn to talk at all?  Well, it all starts with good mimicry.  Many young male songbirds will learn the songs of their neighbors, called song sharing, in order to help with the establishment of territory and attraction of a mate.  Males will often respond to a rival male with the same song, or a song they both know.  In some birds, the larger the repertoire of sounds, the more likely they are to find a mate. 

Still other birds such as the Greater Racket-tailed Drongo, have been found to preferably learned the alarm calls and mobbing calls of the other species in their area over all other sounds.  Learning the context of calls can be an advantage in this situation since these calls can then be used to recruit other nearby species to help scare away a predator.  

Mimicry can be used as a way to fit into the flock.  For example, Yellow-naped Amazon Parrots form regional dialects between flocks, which are unrelated to genetics.  This means that new parrots joining the flock must learn that flock's dialect.  It can be seen how being a good mimic could be advantageous in fitting in and being accepted by the new flock.
Parrots and Macaws are some of the bird world's best mimics
Parrots are naturally very social animals and use their calls and body language to communicate with their flock.  When we keep parrots in our homes, we as humans become their flock.  Parrots will naturally imitate the people they live with and try to establish a means of communication, just as they would the birds in their wild flock.  When a parrot imitates a word, most people are initially excited that their bird said something they understand and give the parrot attention.  This reinforces saying those words more often.  But this does not mean the parrot is talking.  He is merely repeating a noise that gets attention.  The reaction reinforcing the behavior does not have to be from a human either. Nemo, our African Grey Parrot, loves to mimic Locust, our Red-legged Seriema, because she also gives a (very loud) response.

Once a word is in Nemo's repertoire, we reinforce not just saying specific words or sounds, but saying them after we give the corresponding specific cue phrases.  Some of these cues and response words are put together for Nemo's “fairy tale” (a routine we’ve trained Nemo to do during his part of the bird show).

Nemo the African Grey Parrot is one of our most prolific "talkers"

So, our parrots can correctly respond to cues, but can they actually talk?  Well, not much that we know of, but only because we haven't taught them the meanings behind any of the words they say.  For example, when we ask Nemo, "what does a kitty cat say?", he responds with "Meow".  But, since Nemo has probably never seen a real cat meowing, he won't make any connection between the animal "cat" and the sound "meow", but he knows that when we give the cue phrase and he says "meow" he gets a treat. 

 In order for a bird to learn the meaning of a word and really "talk", they must have some context in which the word applies and be able to interact with it in order to really understand the word's meaning.  One African Gray parrot named Alex is now well known for his demonstrations of word comprehension to the scientific community.

While Nemo has never been taught what words mean, he seems to have figured out the meanings of a few words himself. When changing his water, Nemo often makes the sound for water without being cued.  One day during the middle of a show, Nemo told Josh, another show trainer, "Wagner next."  Wagner, our Red-tailed Hawk, was next in the order of birds in the show! Possibly a coincidence, but it just goes to show that we honestly don't have any idea how much Nemo really understands.

Submitted by Michaela Henneberg, World Bird Sanctuary Trainer, Stone Zoo, Boston

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