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

Thraupis episcopus

Tyrannus melancholicus

Turdus ignobilis

Zonotrichia capensis

Thraupis palmarum

Turdus fuscater

Zenaida auriculata

Myiozetetes cayanensis

Sicalis flaveola

Stilpnia vitriolina

Milvago chimachima

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