What is this?

I mentioned that I saw 3 new species of birds today. But I'm not sure about this one. It looks like it belongs to the Bulbul family but my limited book doesn't have something like this. It's got this Mohican feather that it can raise at will. In fact, now I'm not even sure if the bird I named as Yellow Bittern is in fact a Heron... I've got to get a more complete book!

PS; I came across 5 of these while jogging at Kent Ridge today (19 Mar). I've found the name of this bird: it's a White-crested Laughingthrush.

Chup