ajohn

It's not a Little Bunting, which would show more rufous, especially on the face (including the supercilium) and there would be a blacker border to the ear coverts and cleaner white underparts.
The slightly yellowish underparts, streaked flanks and relatively poorly marked head pattern all point towards female Black-faced Bunting. There are several of these along the main AFCD path at Mai Po at the moment.