Yes, the record of Rufous-bellied Niltava in Tai Po Kau is now confirmed!!! I think...... So ... it should be the first record for HK!
The bird clearly show uniform rufous breast to underpart even to the vent. And it is bright blue from the forehead to the nape. Those are the main features of Rufous-bellied Niltava.
Rufous-bellied Niltava is also found in Guangzhou based on the following link.
http://www.cnbird.org.cn/resust.asp?txtsearchstr=Rufous-bellied+Niltava
Hence, Rufous-bellied Niltava may be overlooked and misidentified in the past because it is rather difficult to see clearly under forest especially with dark light condition.
All the records regard to the bird was seen are as follow:
The first seen of the bird was on 5 Jan 2008 on red walk.
Second time: on 8 Feb at picnic area
Third time: photographed by Allen.
Fourth time: on 10 Feb near the entrance of the four-colour walk
Fifth time: photographed by ypakwai