It is the most demanded route of the three that the Sanctuary has for bird watching. It is called Old River because it was the old riverbed of the La Leche or Lercanlech river, which used to flow towards the district of Túcume and in 1983 it devastated 0.5 km of Huaca La Merced.

It consists of a comfortable route of almost 800 meters without great slopes, in the heart of the Pómac Forest and where you can see various species typical of the dry forest, such as the two-colored hawk, the Lineated Woodpecker and the Pale-legged Hornero, better known as chilalo, enjoying the different songs and colors of these and other species with which this ecosystem is shared.