Zoology

The Syrinx and its Role in Speech



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"The Syrinx and its Role in Speech"
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Songbirds and parrots, and parrot related species, for example; communicate very similarly to the way humans communicate. The similarities of these birds, to humans, will be detailed in the following article. Perhaps you have seen videos on You've Been Framed of Budgies and Parrots, and other parrot related species, talking, singing, and whistling tunes they have heard on the radio and television. Or you have, or have had, a bird of your own that can talk, or know someone who owns a talking bird.

A songbird, can also be referred to as an oscine, and can produce "sound notes" (bird song), from a specially developed vocal organ. This vocal organ is used to different extents in parrots for example. Because there are many domesticated parrots kept as pets, they use their "voice box" to mimic voices for example, or surrounding noises that can be heard on the television or radio. Songbirds use their bird song to defend territory for example, or attract mates, or inform others as to their whereabouts. If songbirds produce a complex sound, that can be heard above all other "songs", then the more chance they have of attracting a partner, as they have a "sexier" song. They can also produce higher pitched sounds for alarming other birds of danger or contact, from predators for example.

Animals which can imitate and develop sound, and can learn throughout their adult life, are referred to as "open-ended vocal learners". Parrots and related species fall into this category.

Research has been done by scientists, on "open-ended vocal learners", and it is apparent that the bio-molecular structure is the same in the birds, as it is in mammals. Glutamate is a "molecular messenger" in the brain, called a neurotransmitter. (Glutamate is the most common neurotransmitter in the brain.) There are receptors in the brain of the "singing" birds that rely on this neurotransmitter, enabling them to create the sounds they do.

Researchers have already clarified that these receptors had been found in mammals with complex vocalization; in human brains, twenty-one such receptors had been identified. It later became apparent, after extensive research on the brains of deceased "open-ended vocal learners", that they have the same twenty-one receptors which had been identified in humans. There are higher levels of glutamate receptor expression in birds capable of more elaborate song and speech. The fact that birds have these same receptors, and are still developing, could be down to evolutionary pressures, and the fact that birds need to produce complex sounds to alert other birds, attract mates and defend their territory.

Cage birds copy sounds heard in their environment, similarly to those wild birds mimicking songs or "danger" alerts. I had a talking budgie, called Bob, and it was fascinating to listen to him going through his vocabulary. He sounded just like me, as most of the words and phrases he had picked up where from me, as I paid the most attention to him. Budgies are a small parrot; therefore have similar voice boxes, for example, to a parrot. Having owned an African Gray for the past year, I also know how quickly they can pick up words and phrases, and mimic various sounds it hears perfectly, upon practice. My parrot, called Charley, is currently into whistling Glenn Miller tunes, and barking like the dogs next door. Charley would also mimic Bob the budgie, who would sit talking in one corner of the room, setting Charley off on one of his rants. If they hear something often enough, they will pick it up and repeat it; although, they might only have to hear something once, and remember it.

There are only three orders of mammals that can learn by imitation; the first being humans, followed by bats and dolphins, and then three orders of birds. Therefore, learning by imitation can be referred to as rare.

The "parrot" tongue operates in a complex way, like the human version does; it is the way that the "parrot" tongue operates, and modulates speech patterns, that enables parrots, budgies, and other related species to talk.

Two processes make up the vocal sounds emitted by humans, and are as follows:

The larynx serves as a human voice box, and generates vibrating energy in a wide range of frequencies, it is this that produces sound, and this is the first stage of the first process. The second stage is where some of the vibrating energy produced by the larynx, is filtered by the mouth and nose, tongue and throat, for example, as they absorb some of the frequencies as the vibrations travel from the larynx. Although, on the other hand, these features can also enhance some of these vibrations. Ranges of frequencies that remain strong even after this filtering process, are known as formants.

Formants can be produced in humans by quick tongue movements; this movement is what alters the frequencies of the vibrations.

But how vocalizations are controlled in parrots - and most animals, for that matter - is not that well understood, although believed to be a similar process to that of a human.

For instance, if a parrot moves its tongue rapidly when speaking, as a human does, it is not clear whether or not those motions are enough to change the formants of their speech, as it does in humans.

It could be that the changes heard in parrot speech, is merely down to their own voice box, which produces vibrating energy, and filters the frequencies itself, and is therefore, not as strongly affected by their tongue or any other part of the vocal tract that could potentially have been involved in speech production. A parrot's voice-box is not called a larynx, as it is in humans, although it is similar, and is called a syrinx.

The syrinx is located at the base of the trachea, and there are no vocal chords attached. It is where the trachea forks into each lung, that the syrinx rests, and because of this situation, it enables some birds to produce more than one sound at a time. Another reason why some birds can produce complex sounds which would often be unexpected. Syrinx is the Greek word for panpipes, perhaps the image of panpipes will enable a better understanding as to how complex sounds can be formed from little birds.

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