Below is an extract from one of my recent letters in reply to a query about the song of the Indonesian shama.
When we think of the Indonesian shama, the bird that springs to mind is stout, with short tails and a melodious song that are entered for shama song competitions in Indonesia. These competition type birds are usually referred to as the Medan shama as the best birds for Indonesian song competitions come from this province.
However, there also shamas in Indonesia that look much like the Malaysian, Thai or Vietnamese species (“Malaysian shama”) which are smaller than the typical Medan shama and with somewhat longer tails. Such birds are not generally popular in Indonesia where there is only one criteria for a competition shama and that is its song.
The longer tails and vigorous display of the Malaysian shama tend to detract from the quality of the song. This is not to say that there is no demand for such birds in Indonesia. There are hobbyists there that appreciate the beauty, grace and display of birds with long tails and these rare birds are much sought after.
In Malaysia, Singapore and Vietnam, points are given in competition for grace, beauty and display but these receive no points in Indonesian shama competitions where only the song is judged.
The song of the Medan shama is longer between pauses than the Malaysian shama. I would estimate that the song between pauses is about twice as long.
The song of the Medan shama is also more mellow and melodious. Where a song is long between pauses it is unlikely to be loud since the effort must go into the length of the song rather than its loudness. The song is also less shrill than that of the Malaysian shama. I would characterise the song of the Malaysian shama as being more aggressive and wild than the Medan shama.
Display in the Medan shama is usually limited to a simple up and down motion of the tails between pauses in song. Bear in mind that a vigorous display will adversely affect the quality of the song in the same way as a person who dances and sings at the same time will be able to concentrate less on his song and his song will suffer in consequence.
As a whole, I prefer the Malaysian type shama and this is what I breed.