The Olive-winged Bulbul Pycnonotus plumosus is a common bulbul found in the lowlands and offshore islands but could be very easily misidentified.  The olive fringes on the wings may not be visible in low light while the Red-eyed and Cream-vented bulbuls also display red iris.  I find the quicker way is to look for the streaking on the ear coverts.