
These are species with at least one recorded territory in China, not a national checklist: a bird list from eBird or Avibase is more complete. The counts follow recording effort as much as wildlife, so a country with more visitors and more naturalists will show more of both.
The species with the most open occurrence records in China, among those a photograph exists for. Most recorded is not most numerous: it rewards animals that are common, conspicuous and live where people go.

Pycnonotus sinensis

Spilopelia chinensis

Pica serica

Acridotheres cristatellus

Copsychus saularis

Turdus mandarinus

Passer montanus

Egretta garzetta

Lanius schach

Zosterops japonicus

Parus cinereus

Pycnonotus jocosus
The reference database has no regions filed under China.
The field guide covers China on the map, but none of its species have an entry written for them yet.