
These are species with at least one recorded territory in Czechia, 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 Czechia, among those a photograph exists for. Most recorded is not most numerous: it rewards animals that are common, conspicuous and live where people go.

Parus major

Dendrocopos major

Turdus merula

Sitta europaea

Larus cachinnans

Pica pica

Picus viridis

Garrulus glandarius

Emberiza citrinella

Columba palumbus

Cyanistes caeruleus

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