Before and after

It was not easy initially to identify this bird because of its moulting form.  I finally managed to find out this is a moulting sub-adult Oriental Magpie Robin.
     Birds general moult as they develop or to replace old feathers.  They also change colours when in breeding stage, e.g. the Chinese Pond Heron, sometimes transforming into totally different colour plumage.

Oriental Magpie Robin

The Chinese Pond Heron, before and in breeding plumage.