Andean forests not only provide habitat for many migrants, they play a crucial role in the process of recycling water to provide rain for the agriculturally rich western lowlands. The interruption of this process can have a devastating impact not only on the lowland rainforest birds, but also on the national economies that benefit from lowland cash crops. Protecting habitat for the migrants also protects economies that depend on a healthy environment. Because the soil is fertile, rainfall is abundant, temperatures are mild, and insect-borne diseases are largely confined to the lowlands, the highlands of the Andes have historically maintained relatively large human populations compared to the Amazonian lowlands. By saving the forests, watersheds are protected, thereby preventing soil erosion, reducing flooding, and providing water and energy for people and crops.
Andean forests are among the most biologically diverse in the world.
Creating adequate reserves may not only ensure the survival of hundreds of bird species, including migrants, but will also preserve countless plants and insects. These may have as yet unknown medicinal properties, that could provide cures for cancer and other benefits to human health and science. When migratory birds arrive in the Andes' lush foothill and montane forests, they come into contact with hundreds of resident species. Many of the Andean birds congregate in large mixed-species flocks, which migrant Canada, Blackburnian, and Cerulean warblers join and so become part of this social system. Pewees and Alder Flycatchers do not join flocks but set up territories in patches of forest that they defend against members of their own species.