The Inca tern is a near-threatened species of tern in the subfamily Sterninae of the family Laridae. It is found along the Pacific coasts of Chile, Ecuador and Perú, and has appeared as a vagrant in Central America and Hawaii.
Region
Humboldt Current along the Pacific coasts of Peru, Chile, and Ecuador
Typical Environment
Occurs primarily along the cold upwelling zone of the Humboldt Current, hugging the arid Pacific coasts of Peru and northern to central Chile, with smaller numbers reaching Ecuador. Breeds on offshore guano islands and rugged coastal cliffs where crevices and burrows are available. Often forages nearshore over schools of anchovies and sardines, and gathers around harbors and fishing vessels. Vagrants occasionally appear north into Central America and rarely as far as Hawaii.
Altitude Range
Sea level to 100 m
Climate Zone
Arid
Ease of Keeping
Beginner friendly: 1/5
The Inca tern is instantly recognizable by its elegant white moustache-like facial plumes set against slate-gray plumage. It is tightly tied to the cold, nutrient-rich Humboldt Current and often follows fishing boats and marine mammals to find schooling fish. Colonies frequently occupy rocky guano islands and coastal cliffs, sometimes using man-made structures for nesting. Its flamboyant bill and leg colors intensify during breeding and may signal individual quality.
Two adults and a juvenile (left) in Lima, Perú
Large flocks may occur where conditions are suitable, as here on the Islas Ballestas off the Peruvian coast.
Temperament
social and active
Flight Pattern
agile flier with rapid wingbeats and deft hovering before short plunge-dives
Social Behavior
Highly colonial, nesting in crevices, burrows, and cavities on cliffs and guano islands. Both parents incubate and feed the chicks, typically from one or two eggs. Outside breeding, flocks gather along productive coastlines and often associate with sea lions, dolphins, and fishing vessels.
Migratory Pattern
Resident
Song Description
Vocalizations are loud, harsh, and cat-like, with mewing notes and rasping calls around colonies. Flight calls include sharp, chattering phrases used to maintain contact while foraging.
Plumage
Smooth, dark slate-gray body with clean white, curling moustachial plumes on the face and a narrow white trailing edge on the wings.
Diet
Feeds mainly on small schooling fish, especially Peruvian anchoveta, and also takes sardines and other pelagic baitfish. It performs shallow plunge-dives and surface-dips, often snatching prey chased to the surface by predators. Frequently scavenges fish scraps behind boats and capitalizes on feeding frenzies near marine mammals. In lean periods, it may take small crustaceans and other marine invertebrates.
Preferred Environment
Nearshore waters over upwelling zones, surf lines along rocky coasts, and channels around offshore islets. Common around harbors, piers, and fishing fleets where prey is concentrated.
