Why birds sing.

[The post below is largely taken from my response to an email from NGTC sometime ago.]

It has long been accepted that birds sing to conquer territory, to defend territory or to woo a mate but is there some other reason why birds sing?

In his book, “Why Birds Sing - a journey into the mystery of bird song”, the musician David Rothenberg suggests that birds may also sing because they are happy, much as humans do. He describes the song of certain birds and considers why they sing.  Here is Rothenberg’s description of the shama’s song:

“Soon he’s [the Taveta golden weaver] eclipsed by the white-rumped shama, a virtuoso explorateur.  One new phrase after another.  Anything we play is just a challenge for him.  An orange thrush of the tropics, this guy keeps coming back with a new variation.  Whatever we feed him, he has a louder retort.  Every song he sings seems brand new.”

“Wait a minute, I thought these songs were innate,” I ask Pestel.  “Don’t’ these guys need just one simple song sung as well as possible to do the job?”

            “Calls,” whispers Pestel. “Bird calls are innate.  Those are the sounds they make with specific meanings: ‘Where are you?’ or  ‘I’m hungry’ or ‘watch out, a hawk’s circling above.’  Songs are something else again.  If they’re complicated, they have to be learned.  And the birds can only learn these songs at certain sensitive times in their lives.  Songs help them stand their ground and lure in mates, but they, like our music, don’t have such a clear message”

[DDS: I don’t think it is correct that birds can only learn complex songs at certain sensitive times in their lives.  I accept that the best time to learn new songs is when the birds are very young or during the molt.  However, my experience is that an “open-ended learner”, such as the shama, can learn new songs at almost any time.  I have come across shamas that were already in good form that were able to learn the song of another species after listening to its song for only 5 minutes.]

Here is Rothenberg’s description of the stages of the song learning process:

“One of the early meanings of the verb to record was “to learn a tune.” Ornithologist Daines Barrrington, in the late eighteenth century, used the word to explain how birds learned to sing. “The first sound is called chirp, the next is a call; the third sound is called a recording, which a young bird continues to do for ten or eleven months til able to execute every part of his song. When perfect he is said to sing his song round.”

Rothenberg finally ends the book with these words, “Why do birds sing? For the same reasons we sing – because we can.  Because we love to inhabit the pure realms of sound.  Because we must sing – it’s the way we have been designed to tap into the pure shapes of sound…..”

My own experience seems to confirm Rothenberg’s hypothesis – that sometimes the shama sings for no other reason than that it enjoys doing so. I briefly consider below the different types of the shama’s song as I have known them.

The sub-song

The sub-song is usually heard in the late afternoons and especially on rainy days. The notes are much more variable than its loud song.  While pleasant to the human ear, it seems unstructured and appears to be random warbling and not as coherent as the primary song. 

It is not often appreciated that there are different levels of loudness in the sub-song of the shama.  Usually, it is heard as a soft twitter when the shama is at rest but it can also be quite loud, though not as loud as when the bird sings its territorial song.

The adult male shama will also sing its sub-song during the molt.  This is the time when it best learns new songs after the juvenile stage.  In Indonesia, the serious hobbyist will surround his molting shama with other songbirds during the molt so that the shama can learn to imitate their songs and incorporate them into its repertoire.

It would seem that the shama uses its sub-song as a learning tool to learn new songs or to recollect tunes that it might not have used for some time. Owners of shamas have often commented that after the molt, the bird has new tunes and he has no idea where or how the tunes were picked up.

It is generally accepted that that the young shama practices its song learning by vocalizing its sub-song.  The youngest shama that I have come across singing its sub-song was 14 days of age - only 3 days after it had left the nest.  Clearly, it was learning its song in the same way that a child would learn a poem or song by reciting the words over and over again.

I have also often come across adult shamas that sing their sub-song when they are not in molt.  The bird may sit on its perch without moving much for an hour or more, singing its sub-song.  It seems to find this soothing and calming, at least this is the impression I get.  This brings to mind Rothenberg’s view that a bird may sing because it enjoys doing so.

The in-form shama may also sing what seems to be a cross between a sub-song and loud song when it is alone.  Such songs may be sung throughout the day, without seeming to tire the bird.

The aggressive song

This is a loud territorial song that the shama in good form sings when it is confronted by one or more other shamas that challenge it, such as at a shama gathering (chai tio).  I think all the noise excites it. The white patch of feathers on its rump is raised and it is alert and ready to do battle. The song is a ringing challenge to the other birds that it is defending its territory. 

We need to appreciate that the shama is territorial in nature i.e. it requires a territory to mate and to raise its young and it will try to protect this territory against intruding shamas.  For the caged shama, this would normally be the home of its owner or the aviary where it is housed. 

If a strange shama is brought into the home, the resident shama in good form will react by singing its aggressive song to herald that a stranger is intruding into its territory and to drive out the stranger. A shama that is taken to a chai tio, is outside its territory.  There is therefore no need to protect it. In fact, the shama that is not used to being brought out of the home, may feel intimidated in the strange surroundings and may not sing at all.

In the case of a bird in a cage that performs at a chai tio, I would think that it has come to regard the cage and the area around it as its territory.  If this is correct, the shama at a chai tio that responds to the challenge of the other shamas, treats the cage and its surrounding space as its territory and tries to defend it with its song.  This could explain why most shamas that sing well at home fail to perform, or to perform as well, at the chai tio.

Owners are often surprised that their shama which sings well at home, may not sing at all when brought to the chai tio.  Once we understand that the bird finds no need to sing as it is not defending its territory, we can take steps to train our birds to accept the cage as its territory and to protect it, provided they have the strength of character to do so.

A shama that is intimidated by other shamas may show signs of stress. A clear indication of stress is when the shama fluffs out its body feathers and adopts a posture that suggests that it is prepared to fight.  In fact, this is a defensive, and not an aggressive posture.  Whilst the posture seems threatening, it is a sham and a shama that does not have a strong character adopts it to try to bluff its opponent into thinking that it will defend itseld.  When I see this in a male shama, I reject it as a potential breeder.  In consequence, none of my shamas have this trait.  If they are not in form they may not react to the other shamas but they do not fluff.

  

The alarm song

When the shama is startled by a sound that it may regard as threatening, it sings a song that is loud and which suggests that the bird is excited.  This is an alarm song.  When this song is heard, all the other shamas within earshot will also sing this type of song.  The songs will usually last for a few minutes before dying down to allow normal life to resume.

The loud song that the shama sings when it is in good form

A shama that is in good form will sing for much of the day even though its cage may be in a secluded place in the home and there are no shamas nearby to challenge it.  It is possible that the shama is singing to announce to other shamas that this is its territory.  Another reason, which may be just as valid, is that the shama in good form feels exuberant and expresses himself in song.

The nest-box song

When the birds are paired and before the female lays her eggs, the male may spend quite some time in the nest-box.  Whilst in the box, the male will usually sing what seems to be a sub-song.  It is very soft and seems to invite the female to come to the box.  The female often does so.

I have also heard the twittering song that the male shama sings just when it is about to mate with the female.  The mating that I have seen (and I have seen it many times) usually takes place in the early morning or late evening.  The female may be on a lower branch than the male.  Without prior display, the male suddenly flutter down to the female all the time singing his twittering song somewhat similar to the song that he sings while in the nest-box.  The mating itself lasts a second and it is over and so is the song.

The aggressive love-making song

A male that has been for some time with a female and seems to be completely compatible with it may suddenly seem to attack it.  There is a furious onslaught during which the male will sing a very aggressive loud song when he is a few feet away from the female and what seems to be an aggressive twittering song when he is close to her.  He will chase her and when he is close to her he will peck aggressively at her. 

Close observation will show that he is pecking at her body that is covered by her wing feathers.  He does not peck at her head which could cause her damage or even kill her.  The whole episode may last a minute or so. At the end, the male will fly away and rest on a branch whilst he pants in exhaustion.  The female fluffs her ruffled feathers and goes about her way as though nothing has happened.  No mating takes place during the encounter.

Conclusion

This post sets out the songs of the shama that I have heard in the bird’s various moods.  The melodious and tuneful nature of the songs makes the shama one of the foremost songbirds anywhere in the world.