Over 400 species of birds have been found in the area. The area is most famous for the Great Dusky Swift, hundreds of which can be seen flying through the mist of the falls, and which nest on the rocks behind the falls.
The Toucan family has a few representatives to be found here and the large Toco Toucan is commonly seen as well as the Chestnut-eared Aracari, Saffron Toucanet, and Red-breasted Toucan. Woodpeckers seen were the Ochre-collared Piculet, Yellow-fronted Woodpecker, White-spotted Woodpecker, Blond-crested Woodpecker and Campo Flicker. The Flicker was often seen on grassy area at the entrance along with Southern Lapwing, Saffron Finch, and Plush-crested Jay.
There are Hummingbird feeders at a house in a town nearby where we saw Scale-throated and Planalto Hermit, Black Jacobin, Black-throated Mango, Violet-capped Woodnymph, and Versicolored Emerald.
Walking the trails above the falls yielded some excellent birds including a pair of nest building Surucua Trogon, Rufous-capped Motmot, Rusty-breasted Nunlet, and White-bearded Manakin. Tanagers were well represented including Magpie Tanager, Red-crowned Ant-Tanager, Hepatic, Sayaca, Fawn-breasted, Black-goggled, and Green-headed Tanager. Scaly-headed Parrot and Squirrel Cuckoo put in an appearance.
Near the falls, a Double-collared Seadeater was seen, but the most interesting sighting was a duck that flew by. Due to the lighting, only a silhouette could be seen, but it gave every appearance of a Merganser. However, the only Merganser on Argentina’s species list is the extremely rare Brazilian Merganser. Historically they are known from the area, so it would not be totally out of the question. Tantalizing but inconclusive.
As expected a good number of the Tyrant Flycatcher are in the area, including Planalto Tyrannulet,Russet-winged Spadebill, Cattle Tyrant, Sirystes, Great Kiskadee, Boat-billed Flycatcher, Three-striped Flycatcher, Variegated Flycatcher, and Black-crowned Tityra. Thrush-like and Olivaceous Woodcreeper were seen. Swallow species included White-winged, White-rumped, Black-collared, and Tawny-headed.
