The easiest place to spot the black howler is the gallery forest across from the visitor center at the Esteros del Iberá, just outside Colonia Carlos Pellegrini (the final destination of my recent 4WD adventure), in Corrientes province. On this short signed nature trail, you’re likely to come across the howlers and, if not, you may well hear them at night, as their calls carry across the waters of Laguna Iberá.
I had been to Colonia Pellegrini several times before but, in a recent drive through the Sierras de Córdoba, I also learned that there is a black howler rescue center near the town of La Cumbre. Most of the animals come from the pet trade, and the center accepts volunteers who want to work with them for a minimum of three weeks, “teaching monkeys to be monkeys.”