The town of Tárcoles is a small community of a few houses, restaurant and hotels. What is best known in the area are the tour operators called Crocodile Man Tours and their restaurant. Tárcoles is known for its river with the same name. The best way to explore this area is by boat. The mud flats and the mangroves contain a vast number of shorebirds, seabirds, and mangrove specialties. American Crocodiles are very abundant and it is typical to find 13 feet long individuals.
The mangroves are quite important and are home to Mangrove Vireo, Mangrove Cuckoo, the endemic Mangrove Hummingbird, Mangrove Warbler, Rufous-necked Wood-Rail, Panama Flycatcher, and American Pygmy-Kingfisher to just mention a few. Other good birds include Double-striped Thick-Knee, Roseate Spoonbill, Southern Lapwing, Black-necked Stilt, Boat-billed Heron, Common Black-Hawk, White Ibis, Magnificent Frigatebird, Bare-throated Tiger-Heron. Reptiles, such as the American crocodile, caiman, common basilisk and large iguanas, are also easily seen.
The Tárcoles River is also called the Grande de Tárcoles River or the Río Grande de Tárcoles. It originates on the southern slopes of the Cordillera Central volcanic range and flows in a south-westerly direction to the Gulf of Nicoya. The river is 111 km long and its watershed covers an area of 2,121 km2, which encompasses around 50% of the country's population.
The river is the most contaminated river in Costa Rica, carrying much of the sewage from the central towns and cities. The river's watershed drains approximately 67% of Costa Rica's untreated organic and industrial waste and is considered the most contaminated river basin in the country. It was also affected by a leak of 400 thousand liters of diesel fuel by the state-owned Costa Rican Petroleum Refinery in 2000 which further damaged the ecology of the river and its immediate surroundings.