
These are species with at least one recorded territory in Finland, 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 Finland, 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

Cyanistes caeruleus

Phylloscopus trochilus

Ficedula hypoleuca

Regulus regulus

Acrocephalus schoenobaenus

Erithacus rubecula

Acanthis flammea

Larus argentatus

Chloris chloris

Hirundo rustica

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