The Macuco trail is the wildlife walk. A few kilometres through forest away from the falls circuits, it holds capuchin monkeys, agouti, toucans and a good chance of the forest birds that the main walkways miss entirely.

The upper and lower circuits at dawn hold coatis in troops — bold, food-obsessed and genuinely a nuisance around picnic areas — along with plush-crested jays, great dusky swifts nesting behind the falls themselves, and swallow-tailed hummingbirds.

The Garganta del Diablo walkway, out over the river to the Devil's Throat, is the landscape highlight and also good for swifts and for the vultures and caracaras riding the spray thermals.

The forest at night, in the small area accessible on the park's moonlight walks, adds a different soundscape and the possibility of nocturnal mammals.

The wider Atlantic forest around the park holds jaguar, ocelot and tapir. None is realistically seeable from the walkways, but the population is real and the reserves nearby are part of a serious corridor project.

The falls are impressive year-round; higher water follows the summer rains, and winter brings more comfortable temperatures and fewer insects.

Practicalities

Puerto Iguazú is the base on the Argentine side, with an airport and easy connections from Buenos Aires. The Brazilian side offers the panoramic view and takes half a day; the Argentine side has the walkways and the wildlife, and deserves a full day at least.

Arrive at opening time. The park train and circuits are crowded by mid-morning, and the same walkways are quiet and full of birds an hour earlier.