This is great. Thank you for posting, and especially thank you for making the effort to collect a series of photos that allow us to piece the ring number together. Although not all digits on the ring are visible, there is enough here that I can work out the rest and can give you information about this individual. The ring number is FP58010 (the smaller lettering is the contact details, so that if someone finds the ring they can return it: it is a London contact address because we used to use British rings).
This bird was ringed at Mai Po on 24 November 2004, in gei wai #13 (just next to the Education Centre). Although the exact age at the time of ringing could not be known, it was known that it was at least one year old (i.e. hatched in 2003 or before). With a time of 12 years and 4 months since ringing, I believe this is the oldest ringing recovery ever recorded in Hong Kong. We have very little information about movements (or in this case, lack of movement) or lifespan of Little Egret in Hong Kong, so this is very useful information for us.
Congratulations on such an interesting sighting, and once again thank you for reporting this sighting and for managing to take such good photos that we are able to get the information about this bird. There have been a few cases when it's been possible to read the ring on a bird from photos on the website, and I'd encourage other photographers to post pictures of ringed birds here whenever possible.