In IOC 10.2, no mention is made of non-breeding locations for the nominate or nigripes and so residency is implied, the former's southernmost distribution in that area being listed as India to Philippines. Perhaps ringing data might give some idea of movements. That said, nominate Little Egret is quite a coloniser, and so vagrancy shouldn't be unexpected. For example, I've seen Little Egret on Ascension Island. From memory, Pete Carr has recorded individuals on BIOT Indian Ocean islands, but I can't remember which ssp.
MJB