ajohn

I agree this is a common reed bunting.

Note the large size, very heavy bill and chestnut shoulder. The eastern subspecies recorded in HK are typically colder in plumage tone than European birds, hence Mike T's comment.

As Mike K mentioned, an individual was trapped in Gei Wai 8 last weekend (perhaps the same bird?) but it's a very difficult bird to see in the field in HK so well done!