many thanks for your comment and pointers. I have posted a similar photo at the workshop, which shows the full face of the bird and the space surrounding the bird.
I cropped the original photo b'cos the black framework of the aviary was directly above the head of the bird in this photo - after some thought, I have decided to sacrifice the space to get rid of the distraction from the black framework.
I hope to get a better photo next time when I visit the aviary again. : )
Bali Mynah - my first birds (74) *