The scientific name is Pycnonotus cafer.
It gets its name from the reddish area found at the vent. This can be seen very clearly in the lower photograph. Generally it is dark in colour with white breast & rump. It has a crest & called in Sri Lanka as 'Kondaya' meaning 'haired' because of it.
They consume fruits (eg: plantain & papaya), insects, flower nectar, seeds & buds.
They build a cup shaped nest where they lay 2 to 3 eggs.
This is native to parts of Asia ranging from Pakistan, India & Sri Lanka to southwest China & also some pacific islands where it was introduced later. It had been nominated to be among '100 of worlds worst invaders'.
also see my other post on Bulbul nest: