ajohn

The pale bill is a feature of winter House Sparrows. I don't think it has any taxonomic significance (as far as I am aware).
Looking at photos online, the Long Valley bird looks to me more like a domesticus-type, this one looks more like an indicus/bactrianus. Make of that what you will.

Jonathan, are you claiming the Collared Dove as wild as well? So you have recorded three species that are currently treated as escapes in HK, is that correct?