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

Pitangus sulphuratus

Furnarius rufus

Thraupis sayaca

Zenaida auriculata

Sicalis flaveola

Panthera onca
Tracks along the beach at Corcovado; the animal itself is a gift.

Turdus leucomelas

Vanellus chilensis

Coereba flaveola

Passer domesticus

Hylocharis chrysura

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