Esteros del Iberá: Argentina’s Biggest Unsung Attraction

Argentina’s biggest unsung attraction, Esteros del Iberá is a breathtaking wetland covering up to 13,000 square kilometers (estimates vary), nearly 15 percent of the province. Recharged almost exclusively by rainwater, it’s really a broad shallow river covered by semisubmerged marsh grasses, reeds, and other water-loving plants; it flows almost imperceptibly northeast to southwest, where the Río Corrientes enters the middle Paraná. There are also open-water stretches, however, like Laguna Iberá, a 24,550-hectare lagoon that’s protected under the Ramsar convention on wetlands of international importance.

In terms of wildlife, Iberá is an American Serengeti—while it may lack the faunal biomass of Africa’s famous plain, the variety of species and the sheer numbers of birds, mammals, and reptiles is still awesome. For these reasons, it has attracted the attention of international conservationists such as former Esprit clothing magnate Douglas Tompkins, who has purchased several area estancias to help preserve their natural wealth.

And Iberá needs defenders, as the marshes have a fragile ecology imperiled by mega-hydroelectric developments of the Yacyretá dam, north of the city of Ituzaingó. As runoff from Yacyretá’s rising reservoir seeps into Iberá, deepening waters threaten to break the link between the marsh vegetation and the dissolved sediments from which the plants derive their nutrients. Additional threats have included land invasions and forestry projects.


Esteros del Iberá stretches over an enormous area, but the most convenient access point is Colonia Pellegrini (pop. about 800), a hamlet of wide dirt roads on a peninsula jutting into Laguna Iberá, 120 kilometers northeast of Mercedes via RP 40. Technically, Pellegrini has formal street names, but it’s hard to find signs and, on occasion, even people to ask for directions.

Passable under most conditions, though sections of it are bumpy, RP 40 can be muddy and difficult for conventional vehicles in wet weather. It requires caution and moderate speeds at all times. Eastbound RP 40 to the junction with paved RN 14 is impassable except for 4WD vehicles, and it is especially difficult in wet weather.

Note that Pellegrini has no bank or other exchange facilities. Some hotels may accept U.S. dollars, but it’s better to bring enough money for your stay.

Flora and Fauna

Iberá is a wonderland of biodiversity. Scattered open-water lagoons lie within an endless horizon of marshland grasses, aquatic plants, and embalsados (“floating islands”), which some ecologists have likened to tropical peat bogs. Even relatively large trees like the ceibo and laurel flourish here and in gallery forests along faster-flowing waters.

Biologists have catalogued over 40 species of mammals, 35 species of amphibians, 80 species of fish, and 250–300 species of birds. The most readily seen mammals are the carpincho (capybara), marsh deer, pampas deer, and mono carayá (howler monkey). Less easily seen are the lobito de río (Paraná otter) and the nocturnal aguará guazú (maned wolf).

Among the reptiles are two species of caimans, the rare yacaré overo and the more common yacaré negro. Australians take note: These skinny two-meter creatures are not Queensland’s massive crocodiles and do not pounce out of the swamps in search of human nourishment, though attempting to pet them is not advisable. The endangered water curiyú (water boa) is also present.

Birds species are too numerous to mention more than a sampling, but the signature species include the chajá (crested screamer), mbiguá común (olive cormorant), several species of storks, herons, and egrets as well as many waterfowl, including the endangered pato crestudo (comb duck).

Sights and Recreation

Iberá is a year-round destination, but the summer months can be brutally hot and humid, and rain can fall at any time. Activities include wildlife-watching, hiking on a gallery-forest nature trail, and horseback riding.

Launch tours on Arroyo Corrientes, which involve poling through floating islands where an outboard motor is useless, are available through all the hotels and private guides as well. Canal Miriñay is an alternative that offers better wildlife viewing when the waters rise and wildlife may retreat to the interior of the embalsados.

Two-hour excursions, which cover a lot, begin in the US$18 pp range for one or two people, slightly less for larger groups. As some animals are nocturnal, nighttime tours are also available, especially under the full moon.

Rental canoes and kayaks are available, but kayaks are unsuitable for exploring the marshes, whose dense vegetation makes visibility poor—other than Pellegrini’s cell phone tower, this nearly featureless terrain has few landmarks, and you can’t stand up in a kayak to get your bearings.

José Martín’s Iberá Expediciones (tel. 03773/15-40-1405) does after-dark and full-moon safaris along the Mercedes highway to view nocturnal wildlife.

Pellegrini now has a small museum, the Museo Yjára (Yangapiry and Yaguareté, 4–8 p.m. daily except Tues., free).

Other Practicalities

At the approach to Colonia Pellegrini, immediately before the Bayley bridge that crosses Laguna Iberá, former poachers staff the provincial Centro de Intepretación, the reserve’s visitors center. On the other side of the bridge, Pellegrini’s Oficina de Información Turística (7:30 a.m.–7:30 p.m. daily except Tues.) has good maps and lists of services, with helpful personnel. Hotel staff and guides are also excellent sources of information.

Daily except Sunday, El Rayo (tel. 03773/42-0184) and Itatí II (tel. 03773/42-1722) operate bus services from Colonia Pellegrini back to Mercedes (3 hours, US$8). The El Rayo bus leaves around 4–5 p.m., but Itatí II departs around 4 a.m. This allows locals to make shopping trips and return in the same day, but it’s not so great for travelers who want a full night’s sleep. They will pick you up at your accommodations in Pellegrini, however.

From the Posadas airport, it’s possible to arrange direct transfers for four to six people in a 4WD vehicle for about US$200–225 with Anamatours (tel. 03752/42-0199). From Pellegrini, Trans-Beto (tel. 03757/15-51-5862) and Hugo Boccalandro (tel. 03773/15-40-0929) offer similar services.

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