Newquays bird is indeed a black bulbul. This white headed form (Hypsipetes leucocephalus leucothorax) is most widespead in Vietnam but does occur in small populations in Laos, Cambodia and Thailand
I made some very intresting obsevations on 2 subspecies of the Black bulbuls. At Walsrode we had first several specimens of a total black subspecies and they live piecefully with a kinds of other birds in the Tropical free-flight.
After the last one passed away a new group was obtained, this time of a white-headed subspecies. After quarantaine we released them in the same Tropical free-flight and they started from the beginning on to attack other birds even much bigger ones like doves.
After a while we even had to remove them and place them in another aviary with no other birds !