The Guanay Cormorant found in on the Pacific coast of Peru and northern Chile. Its major habitats include shallow seawater and rocky shores.
Breeding occurs year round with a peak in November and December. The nest is built of guano on flat surfaces on offshore islands or remote headlands. There are up to 3 nests per square meter in high-density colonies.
It feeds mainly on the Peruvian anchoveta, Engraulis ringens, and the Peruvian silverside.

Habitat loss and degradation and over-fishing have resulted in a steady decline of the population of about 30% from an estimated figure of 3 million birds in 1984. This species is listed as NT (near threatened) by IUCN.